The Bud Industries AS-5042-A telescoping linear motion mechanisms have a slide arm length of 20" with 20.87" of travel. Each pair of AS-5042-A panel mounting rails is load rated up to 91 lbs and has a three-piece slide for nearly full extension. These zinc plated, alloy steel telescoping and linear motion mechanisms consists of an outer member, inner member, ball retainer and ball bearings. All types offer a smooth, precise telescoping movement with long service life. Requires two pairs of panel mounting rails per cabinet rack.