Bionic Bigfoot Stoppers Toe Stops 30mm Stem Extra Long Lasting Grip GRIPPY: 59mm footprint for extra bite on the skating surface. PRE-ANGLED BOTTOM: Zero Break In Period. Angled to prevent wheels from touching (guaranteed up to 66mm) LENGTH: 30mm 5/8" Stem COLOR: Greyish White POPULAR: Used my many skaters and designed to meet the high demands of derby and other skating. By Atom Wheels.