Replacement Caster 3 . * Twin Wheel Casters Have Threaded Stem For Extra Security And Safety. * MJM's Exclusive Reinforced Caster System Allows Additional Structural Support To Our Entire Product Line. * Our Positive Engaging Lock Holds The Wheel Securely So There Is No Swivel Movement When Locked. * The Unique Design Allows Easy Movement On Hard Surfaces And Helps Eliminate the Wheel From Falling Into Cracks. * Soft Non Marking Tread. * It Will Not Leave Black Marks Or Leave Groves In Wood Or Vinyl. * Quite Mobility. * Non Rust Plastic Body And Wheels. * High Load Capacity of 160 lbs. * Non Slip Tread. * Double The Tread Surface For Superior Breaking. * Easy Reach Brake Tab. *