RockNRoller RCSTR5X125 5""x 2"" Caster w. Brake; Pack of 2 pcs.;Upgrade caster for the R8RT and R10RT carts; custom-designed R-Trac Wide wheels; 50% wider than typical casters for wider load dispersion over soft terrain; low profile no-flat tires; lightweight and strong polymer hubs; low rolling resistance; incl. nuts and lock washers