High quality sublimation ink is used. This is a sublimated tumbler. Meaning special ink was used to create this design and press it into the tumbler. This is NOT vinyl and we do not use epoxy. The beauty of sublimation is the permanent ink aspect. It will never wash off, never fade, never peel. Everything is handmade so no two items will be exactly a like. The stainless steel tumblers is double-walled to keep drinks cool or warm for a long time, from the first refreshing sip to the very last drop, convenient to use in daily life.