Spring Loaded Door Caster 3 Inch Heavy Duty Rubber Door Wheel 220lbs with Spring Stop DeviceINTEGRATED SPRING DESIGN - Allows gates to open and close freely by automatically adjusting height on uneven ground while eliminating gate sag. The spring clamp acts as a shock absorber when the caster rolls over uneven or rough surfaces. Designed to allow gates to open and close freely by automatically adjusting the height on uneven ground. HEAVY DUTY CASTER WITH STOP DEVICE - The wheel has a maximum load capacity of 220 lbs and can also withstand exposure to chemicals and solvents. Universal fixing system for wooden or metal gates. The stopper helps secure the door. Spring load capacity is 60 kg/132 lbs. When the weight of the door is more than 60 kg/132 lb, the spring loses its elasticity. SHOCK ABSORPTION - Designed to allow doors to open and close freely by automatically adjusting the height on uneven ground. Easy to move and roll, makes opening and closing the gate easier. DURABLE MATERIAL - This gate wheel is made of premium rubber and metal, sturdy and durable. EASY TO INSTALL - Heavy duty universal mounting plate with holes to easily attach to wooden gates or along the horizontal or vertical rails of a tubular farm gate.