Ruberex wheel, double ball bearing, split-level, nickel-plated steel construction offers superior swiveling and weight dispersion. A friction grip stem is precision formed and securely shanked to prevent wobbling. Each caster comes complete with amp cabinet receptacle and four 14-1 round head phillips wood mounting screws. Installation requires drilling a 5/8 in. hole in amp cabinet. The maximum recommended weight is 80 lbs. per caster.