Pet Cargo Metal Castor Wheel for Dog Carrier, 4-Pack, Blue Reversible argyle raincoat Fits Dogit Pet Cargo dog carrier models 500, 600, 700, 800, 900 Includes 4 castors per pack 2 Castors with brakes and 2 without brakes Measures 5-1/2-inch length by 6-1/2-inch width by 4-4/5-inch height