These casters feature a top plate and yoke of zinc-plated ¼” cold formed steel plate or polished Type 304 stainless steel for high quality appearance and long life. Swivel sections feature double ball bearing raceways; axles are ½” diameter. Variety of brake options; scaffolding casters feature a total lock brake to positively secure wheels and swivel. Select NSF Listed models with Prevenz™ Antimicrobial Wheels for use in medical, food, pharmaceutical and other environments that require certain removal of destructive and odor-causing microbes.