Rotates on steel ball bearings. The best answer to keeping burs, mini brushes, drills, diamond points or anything else which fits into a handpiece from being lost. Stop wasting time searching for lost tools- this rotating organizer holds up to 156 items with 108 holes sized for 3/32" shank instruments and 48 larger holes for 3/8" shank tools. Height 3-1/2". Not appropriate for dental burs.