The subscription is tied to your Apple ID and you can use it on all devices which share the same Apple ID.
There are two ways to restore your purchases.

1. Restore in settings #

1. Tap on the settings in GymYou
2. Tap on ‘Restore Purchases’

2. Restore on the purchase page #

If you are trying to use a pro feature without an active GymYou Pro subscription, you get the prompted the purchase page.

1. Tap on ‘Restore’