Integrated spring design: Innovative integrated spring design extends the life of the spring while providing a clean, attractive appearance. Built-in spring clamp acts as a shock absorber when gate wheels roll over uneven or rough surfaces, reducing stress on gate hardware and helping to extend the life of gate posts and hinges. Spring-loaded gate roller: Adjustable spring-loaded support with up to 4.5 cm of vertical travel. Automatically adjusts gate height to surrounding terrain during opening and closing cycles, effectively preventing gates from sagging and maintaining a level fence line. Heavy-duty gate caster: Constructed with heavy-gauge matte black plated steel and dual ball bearings for strong load support. Each gate wheel supports up to 200 lbs, making it easy to operate large, heavy wooden gates, vinyl gates, metal tube gates, or metal swing gates. 360 swivel caster: 4-inch aging-resistant rubber wheel with a 360-degree rotatable top plate. Offers excellent mechanical strength and load capacity, allowing smooth directional movement with minimal effort. Easy to install: Heavy-duty universal mounting plate with three holes for secure attachment to wooden gates using lag bolts. Versatile hole pattern also enables straightforward installation on tubular farm gates or along horizontal or vertical gate tracks. Mounting bolts and screws included.