Poly-on-Poly wheels are shock absorbant, quiet - causing minimal vibration, along with leaving no marks. This allows for prolonged equiptment life. CW354POP-S: 3-1/2" X 1-1/4" Poly-on-Poly Swivel Caster$8.48PriceQuantityAdd to CartWheel Diameter:3-1/2" Thread Width:1-1/4" Wheel Thread Material:Polyurethane on Polyolefin Load Capacity:325 lbs Overall Height:4-5/8 Bearing Type:Ball Bearing Top Plate:2-3/8" x 3-5/8"