diff --git a/wrench-sample/src/main/java/com/example/wrench/BoltLiveData.java b/wrench-sample/src/main/java/com/example/wrench/BoltLiveData/BoltLiveData.java
similarity index 55%
rename from wrench-sample/src/main/java/com/example/wrench/BoltLiveData.java
rename to wrench-sample/src/main/java/com/example/wrench/BoltLiveData/BoltLiveData.java
index beb362d..542866a 100644
--- a/wrench-sample/src/main/java/com/example/wrench/BoltLiveData.java
+++ b/wrench-sample/src/main/java/com/example/wrench/BoltLiveData/BoltLiveData.java
@@ -1,8 +1,9 @@
-package com.example.wrench;
+package com.example.wrench.BoltLiveData;
 
 import android.arch.lifecycle.LiveData;
 import android.content.ContentResolver;
 import android.content.Context;
+import android.content.pm.ProviderInfo;
 import android.database.ContentObserver;
 import android.database.Cursor;
 import android.net.Uri;
@@ -12,31 +13,33 @@
 import com.izettle.wrench.core.Bolt;
 import com.izettle.wrench.core.WrenchProviderContract;
 
-public class BoltLiveData extends LiveData<Bolt> {
+public abstract class BoltLiveData extends LiveData<Bolt> {
     private final String key;
     private final String type;
-    private final String defValue;
     private final Context context;
     private BoltContentObserver boltContentObserver;
 
-    BoltLiveData(Context context, String key, String defValue, @Bolt.BoltType String type) {
+    BoltLiveData(Context context, String key, @Bolt.BoltType String type) {
         this.context = context;
         this.key = key;
         this.type = type;
-        this.defValue = defValue;
         boltContentObserver = new BoltContentObserver(new Handler());
     }
 
-    public static BoltLiveData string(Context context, String key, String def) {
-        return new BoltLiveData(context, key, def, Bolt.TYPE.STRING);
+    public static BoltLiveData create(Context context, String key, String def) {
+        return new StringBoltLiveData(context, key, def, Bolt.TYPE.STRING);
     }
 
-    public static BoltLiveData bool(Context context, String key, boolean def) {
-        return new BoltLiveData(context, key, String.valueOf(def), Bolt.TYPE.BOOLEAN);
+    public static BoltLiveData create(Context context, String key, boolean def) {
+        return new StringBoltLiveData(context, key, String.valueOf(def), Bolt.TYPE.BOOLEAN);
     }
 
-    public static BoltLiveData integer(Context context, String key, int def) {
-        return new BoltLiveData(context, key, String.valueOf(def), Bolt.TYPE.INTEGER);
+    public static BoltLiveData create(Context context, String key, int def) {
+        return new StringBoltLiveData(context, key, String.valueOf(def), Bolt.TYPE.INTEGER);
+    }
+
+    public static <T extends Enum> BoltLiveData create(Context context, String key, Class<T> enumClass, T def) {
+        return new EnumBoltLiveData<>(context, key, enumClass, def);
     }
 
     @Nullable
@@ -65,16 +68,27 @@ private static Bolt getBolt(ContentResolver contentResolver, String key) {
         return new Bolt();
     }
 
-    private static Uri insertBolt(ContentResolver contentResolver, Bolt bolt) {
-        return contentResolver.insert(WrenchProviderContract.boltUri(), bolt.toContentValues());
+    String getType() {
+        return type;
+    }
+
+    Context getContext() {
+        return context;
+    }
+
+    String getKey() {
+        return key;
     }
 
     @Override
     protected void onActive() {
-        context.getContentResolver()
-                .registerContentObserver(WrenchProviderContract.boltUri(), true, boltContentObserver);
+        ProviderInfo providerInfo = context.getPackageManager().resolveContentProvider(WrenchProviderContract.WRENCH_AUTHORITY, 0);
+        if (providerInfo != null) {
+            context.getContentResolver()
+                    .registerContentObserver(WrenchProviderContract.boltUri(), true, boltContentObserver);
 
-        boltChanged();
+        }
+        onChange();
     }
 
     @Override
@@ -82,22 +96,12 @@ protected void onInactive() {
         context.getContentResolver().unregisterContentObserver(boltContentObserver);
     }
 
-    private void boltChanged() {
-        Bolt bolt = getBolt(context.getContentResolver(), key);
-
-        if (bolt == null) {
-            setValue(null);
-            return;
-        }
-
-        if (bolt.getId() == 0) {
-            bolt = bolt.copy(bolt.getId(), type, key, defValue);
-            Uri uri = insertBolt(context.getContentResolver(), bolt);
-            bolt.setId(Long.parseLong(uri.getLastPathSegment()));
-        }
-        setValue(bolt);
+    private void onChange() {
+        boltChanged(getBolt(context.getContentResolver(), key));
     }
 
+    abstract void boltChanged(@Nullable Bolt bolt);
+
     class BoltContentObserver extends ContentObserver {
         BoltContentObserver(Handler handler) {
             super(handler);
@@ -110,7 +114,7 @@ public void onChange(boolean selfChange) {
 
         @Override
         public void onChange(boolean selfChange, Uri uri) {
-            BoltLiveData.this.boltChanged();
+            BoltLiveData.this.onChange();
         }
     }
 }
\ No newline at end of file
diff --git a/wrench-sample/src/main/java/com/example/wrench/BoltLiveData/EnumBoltLiveData.java b/wrench-sample/src/main/java/com/example/wrench/BoltLiveData/EnumBoltLiveData.java
new file mode 100644
index 0000000..ca33896
--- /dev/null
+++ b/wrench-sample/src/main/java/com/example/wrench/BoltLiveData/EnumBoltLiveData.java
@@ -0,0 +1,46 @@
+package com.example.wrench.BoltLiveData;
+
+import android.content.Context;
+import android.net.Uri;
+
+import com.izettle.wrench.core.Bolt;
+import com.izettle.wrench.core.Nut;
+import com.izettle.wrench.core.WrenchProviderContract;
+
+class EnumBoltLiveData<T extends Enum> extends BoltLiveData {
+    private final Class<T> enumClass;
+    private final T defValue;
+
+    EnumBoltLiveData(Context context, String key, Class<T> enumClass, T defValue) {
+        super(context, key, Bolt.TYPE.ENUM);
+        this.enumClass = enumClass;
+        this.defValue = defValue;
+    }
+
+    private Uri insertBolt(Bolt bolt) {
+        return getContext().getContentResolver().insert(WrenchProviderContract.boltUri(), bolt.toContentValues());
+    }
+
+    private void insertNut(Nut nut) {
+        getContext().getContentResolver().insert(WrenchProviderContract.nutUri(), nut.toContentValues());
+    }
+
+    @Override
+    void boltChanged(Bolt bolt) {
+        if (bolt == null) {
+            setValue(new Bolt(0, getType(), getKey(), String.valueOf(defValue)));
+            return;
+        }
+
+        if (bolt.getId() == 0) {
+            bolt = bolt.copy(bolt.getId(), getType(), getKey(), String.valueOf(defValue));
+            Uri uri = insertBolt(bolt);
+            bolt.setId(Long.parseLong(uri.getLastPathSegment()));
+
+            for (T t : enumClass.getEnumConstants()) {
+                insertNut(new Nut(bolt.getId(), t.toString()));
+            }
+        }
+        setValue(bolt);
+    }
+}
diff --git a/wrench-sample/src/main/java/com/example/wrench/BoltLiveData/StringBoltLiveData.java b/wrench-sample/src/main/java/com/example/wrench/BoltLiveData/StringBoltLiveData.java
new file mode 100644
index 0000000..b097fee
--- /dev/null
+++ b/wrench-sample/src/main/java/com/example/wrench/BoltLiveData/StringBoltLiveData.java
@@ -0,0 +1,32 @@
+package com.example.wrench.BoltLiveData;
+
+import android.content.Context;
+import android.net.Uri;
+
+import com.izettle.wrench.core.Bolt;
+import com.izettle.wrench.core.WrenchProviderContract;
+
+class StringBoltLiveData extends BoltLiveData {
+    private final String defValue;
+
+    StringBoltLiveData(Context context, String key, String defValue, String type) {
+        super(context, key, type);
+
+        this.defValue = defValue;
+    }
+
+    @Override
+    void boltChanged(Bolt bolt) {
+        if (bolt == null) {
+            setValue(new Bolt(0, getType(), getKey(), defValue));
+            return;
+        }
+
+        if (bolt.getId() == 0) {
+            bolt = bolt.copy(bolt.getId(), getType(), getKey(), defValue);
+            Uri uri = getContext().getContentResolver().insert(WrenchProviderContract.boltUri(), bolt.toContentValues());
+            bolt.setId(Long.parseLong(uri.getLastPathSegment()));
+        }
+        setValue(bolt);
+    }
+}
diff --git a/wrench-sample/src/main/java/com/example/wrench/MainActivity.java b/wrench-sample/src/main/java/com/example/wrench/MainActivity.java
index d0c0b41..5f88864 100644
--- a/wrench-sample/src/main/java/com/example/wrench/MainActivity.java
+++ b/wrench-sample/src/main/java/com/example/wrench/MainActivity.java
@@ -53,14 +53,14 @@ protected void onCreate(Bundle savedInstanceState) {
         });
 
         wrenchPreferences.getEnum(getString(R.string.enum_configuration), MyEnum.class, MyEnum.FIRST);
-        wrenchSampleViewModel.getBolt(getString(R.string.enum_configuration)).observe(this, bolt -> {
+        wrenchSampleViewModel.getEnumBolt().observe(this, bolt -> {
             if (bolt != null) {
                 activityMainBinding.enumConfiguration.setText(bolt.getValue());
             }
         });
 
         wrenchPreferences.getString(getString(R.string.service_configuration), null);
-        wrenchSampleViewModel.getBolt(getString(R.string.service_configuration)).observe(this, bolt -> {
+        wrenchSampleViewModel.getServiceStringBolt().observe(this, bolt -> {
             if (bolt != null) {
                 activityMainBinding.serviceConfiguration.setText(bolt.getValue());
             }
@@ -80,7 +80,7 @@ public boolean onCreateOptionsMenu(Menu menu) {
     }
 
     @SuppressWarnings("unused")
-    enum MyEnum {
+    public enum MyEnum {
         FIRST, SECOND, THIRD
     }
 }
diff --git a/wrench-sample/src/main/java/com/example/wrench/WrenchSampleViewModel.java b/wrench-sample/src/main/java/com/example/wrench/WrenchSampleViewModel.java
index 8f42609..91deac2 100644
--- a/wrench-sample/src/main/java/com/example/wrench/WrenchSampleViewModel.java
+++ b/wrench-sample/src/main/java/com/example/wrench/WrenchSampleViewModel.java
@@ -5,6 +5,7 @@
 import android.arch.lifecycle.LiveData;
 import android.support.annotation.NonNull;
 
+import com.example.wrench.BoltLiveData.BoltLiveData;
 import com.izettle.wrench.core.Bolt;
 
 public class WrenchSampleViewModel extends AndroidViewModel {
@@ -13,23 +14,26 @@ public WrenchSampleViewModel(@NonNull Application application) {
     }
 
     LiveData<Bolt> getStringBolt() {
-        return BoltLiveData.string(getApplication(), getApplication().getResources().getString(R.string.string_configuration), "string1");
+        return BoltLiveData.create(getApplication(), getApplication().getResources().getString(R.string.string_configuration), "string1");
     }
 
     LiveData<Bolt> getIntBolt() {
-        return BoltLiveData.integer(getApplication(), getApplication().getResources().getString(R.string.int_configuration), 1);
+        return BoltLiveData.create(getApplication(), getApplication().getResources().getString(R.string.int_configuration), 1);
     }
 
     LiveData<Bolt> getBooleanBolt() {
-        return BoltLiveData.bool(getApplication(), getApplication().getResources().getString(R.string.boolean_configuration), true);
+        return BoltLiveData.create(getApplication(), getApplication().getResources().getString(R.string.boolean_configuration), true);
     }
 
     LiveData<Bolt> getUrlBolt() {
-        return BoltLiveData.string(getApplication(), getApplication().getResources().getString(R.string.url_configuration), "http://www.example.com/path?param=value");
+        return BoltLiveData.create(getApplication(), getApplication().getResources().getString(R.string.url_configuration), "http://www.example.com/path?param=value");
     }
 
-    LiveData<Bolt> getBolt(String key) {
-        return new BoltLiveData(getApplication(), key, null, null);
+    LiveData<Bolt> getEnumBolt() {
+        return BoltLiveData.create(getApplication(), getApplication().getResources().getString(R.string.enum_configuration), MainActivity.MyEnum.class, MainActivity.MyEnum.FIRST);
     }
 
+    LiveData<Bolt> getServiceStringBolt() {
+        return BoltLiveData.create(getApplication(), getApplication().getResources().getString(R.string.service_configuration), null);
+    }
 }