Make the most of space with this two tier systemTop tier includes preassembled full extension ball bearing slides: 100 lb slides on 4-3/16" units, 75 lb slides on 3-3/4" unitsItem numbers with P include push-to-open slides on top trayShips notched and bored for recommended use with USE58-300 undermount drawer slides (sold separately)Drawer front not includedMade from 1/2" solid white birch dovetail drawer sides and 1/4" prefinished birch plywood bottoms, all with clear UV finish