Sliders™ – These wheels are the second style of PROTO wheels to come out. They share the same spoked core but are different in the urethane. Sliders™ are harder than Grippers™ and also take a longer time to wear down, even when doing high stress tricks such as sliders (hence the name) and powerslides.PROTO Wheels are made in the USA and have an anodized core for durability. Featuring BUFF Core Technology to reduce dehubbing. All PROTO Scooter Wheels come with bearing removal slots for taking bearings out with ease. These wheels come with High Quality PROTO Murders Bearings Pre-installed. PROTO - STICKERS INCLUDED. 90-Day Limited Warranty.