diff --git a/res/values/default_values.xml b/res/values/default_values.xml
index 1ceed36f..3e8fda2f 100644
--- a/res/values/default_values.xml
+++ b/res/values/default_values.xml
@@ -58,7 +58,7 @@
 	<string name="p_calc_haptic_feedback_duration_key">org.solovyev.android.calculator.CalculatorActivity_calc_haptic_feedback_duration_key</string>
 	<string name="p_calc_haptic_feedback_duration">" "</string>
 
-	<string name="p_calc_ad_free_key">org.solovyev.android.calculator_ad_free_application</string>
+	<string name="p_calc_ad_free_key">org.solovyev.android.calculator_ad_free</string>
 	<string name="p_calc_ad_free">false</string>
 
 </resources>
\ No newline at end of file
diff --git a/src/main/java/org/solovyev/android/calculator/ApplicationContext.java b/src/main/java/org/solovyev/android/calculator/ApplicationContext.java
index 24dc38c3..d022e233 100644
--- a/src/main/java/org/solovyev/android/calculator/ApplicationContext.java
+++ b/src/main/java/org/solovyev/android/calculator/ApplicationContext.java
@@ -1,6 +1,5 @@
 package org.solovyev.android.calculator;
 
-import net.robotmedia.billing.BillingController;
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -10,8 +9,8 @@ import org.jetbrains.annotations.NotNull;
  */
 public class ApplicationContext extends android.app.Application {
 
-	public static final String AD_FREE_APPLICATION = "ad_free_application";
-	public static final String AD_FREE_APPLICATION_P_KEY = "org.solovyev.android.calculator_ad_free_application";
+	public static final String AD_FREE = "ad_free";
+	public static final String AD_FREE_P_KEY = "org.solovyev.android.calculator_ad_free";
 
 	@NotNull
 	private static ApplicationContext instance;