What type of in-app purchase can be transferred to different devices using the same iTunes account?

The reason why non-consumable in-app purchases can be transferred to different devices using the same iTunes account is that they are designed to be permanent and not deplete over time. When a user makes a non-consumable purchase, such as buying an additional level in a game or unlocking full features in an app, that purchase is tied to the user's Apple ID.

When switching devices or downloading the app on another device that uses the same iTunes account, the user can easily restore these purchases without needing to pay again. This feature allows for a seamless experience across devices, ensuring that the user maintains access to the content they've already paid for without having to purchase it multiple times.

In contrast, consumable purchases, which include items like virtual currency or extra lives, are designed to be used up over time and thus cannot be transferred. Subscriptions typically grant access to services for a specified duration and can be managed across devices, but they operate under a different framework and do not represent a permanent purchase. Free trials are temporary access periods and do not involve a purchase at all, which makes them ineligible for transfer.