With 6 Hole Mounting Plate --- Our gate wheel comes with a sturdy universal mounting plate with 6 holes for easy attachment to wooden doors or horizontal or vertical rails along tubular farm gates . Heavy Duty Casters - Our heavy-duty gate wheels have a maximum load capacity of 200 lbs and can also withstand exposure to chemicals and solvents. Spring-loaded design --- Our door wheel features a spring-loaded design that allows the door to open and close freely by automatically adjusting its height on uneven ground while eliminating door sagging. Sturdy and durable --- Our door wheel is made of high quality nylon and metal, which is strong and durable, and can meet your needs well. Shock-absorbing design -- - Our door wheel adopts shock-absorbing design, easy to move and roll, easier to open and close the door.