"Rigid 4 x 1-1/2 caster, mold on urethane"
Swivel 8 caster with 8 x 2 Mold-on urethane wheel
Rigid 8 caster with 8 x 2 Mold-on urethane wheel
Rigid 6 caster with 6 x 2 Mold-on urethane wheel
