This skin is a part of the battle pass Formaction: Act 3 that costs 1000 valorant points. The Lightwave Sheriff is unlocked at level 10 of the battle pass.
This skin is upgradable. There are different levels that changes the look of the skin, it costs 15 radianite points to unlock each level. The different variations can be seen below.
Find all the insight and weapon stats you need to know about Sheriff as a gun in our weapon page.