PlateMate 5 lb. BRICK (Single) - Magnetic Add-On Weight for Selectorized Weight Stack Machines Includes (1) Brick Shaped Magnetic Add-On Weight, 5 lbs. Attaches to metal weights securely with super-strong magnet. Weight Stack NOT Included. Designed specifically for selectorized or stack weight machines. Build strength steadily with 5 lb increments instead of the typical 10 or 15 lb increases. Will not magnetically stick properly to surfaces coated with rubber, urethane, neoprene, vinyl.