This is only a skin and not a coded product.
You need Photoshop to customize or edit this product.
Reaper is a GUI made for mobile devices. I aimed for the following resolution - 2732x2048 for the iPad Pro, but the elements can be scaled down and made to fit lower resolutions. It is highly recommended for you to have Photoshop before you purchase this product. The PNG files, which are included help, but it is best for you have access to the PSDs.
-Sliced UI PNGs
-9 Main PSD Files
-Hovered and Pressed Dynamic Elements