2 Post offers a variety of sliding or fixed shelves for 2 Post racks. They are able to withhold weight from 30 lbs (14 kgs) to 900 lbs (408 kgs). Also the shelves are compatible with threaded, square, or round hole racks, while giving an adjustable mounting depth. 2 Post shelves are designed to hold all types of equipment in any size or weight. The Configurable Relay Rack- 20” Solid is made of 16 GA steel. It has a capacity of 150 lbs (68 kgs) and a shelf surface area of 20” x 17.375” (508 x 441 mm). The shelf can be mounted up-side-down.