... caster 3.Wheel diameter: 200mm 4.Caster material: Plain bearing PU on nylon wheel and only NYLON is availableand . Double brake ... steel balls make,the caster swivel smoothly under big load,PU coated brake pedal protect shoes well.5.Chrome, zinc or nickel ... diameter is from 15mm to 300mm, materials include rubber, TPR, PU, plastic, nylon, cast iron, pneumatic, phenolic and sandwich, etc. Our ...