Poly carbonate pulley wheels are more durable then POM. It is as much more solid material which allows them to last longer. Doesn't flat spot like POM can when over tightened. Can increase travel noise.
1 x Poly-carbonate Wheels with 625zz bearings and center shim.
Durable Poly-carbonate wheels, full metal 625zz bearings.
14g/Bore diameter: 5mm, Outer Diameter: 24mm, Height: 11mm