Tap "Pro feature" on the app's settings screen to purchase it. Once you purchase it, you can enjoy all of the following benefits:
・No more ads
・All BGM, rolling sounds, and decision sounds become available
・Metallic dice colours and the gold app icon become available
・Save up to 1000 favorites and view up to 1000 history entries
・Fine-tune the shape and feel of the dice in more detail
・Priority support
You can choose from three purchase options: Monthly, Annual, or Lifetime. Please see the next item for the differences.