Heavy-Duty Industrial Use: 2 wheels, 6" diameter, 1 3/4" thick, with double-sealed bearings, support up to 5000 lbs for large gates or doors with inverted V tracks. Maintenance-Free: High-temperature sealed bearings in solid steel wheels; no greasing or maintenance needed. Corrosion-Free: Galvanized wheels resist rust and corrosion for indoor/outdoor use. Easy to Install: Package includes 2 wheels, 2 bolts, 2 locknuts, and 2 washers for smooth, precise sliding on V-tracks. Suitable Occasions: Ideal for sliding gates, rolling doors, towing, gym equipment, and moving heavy objects on V-tracks.