Preassembled Rollout Shelf System for 21″ Cabinet Openings. Featuring 21″ Undermount Soft Closing Drawer Slides. – Preassembled and ready to install, mounts to bottom of cabinet. – Soft-closing under mount slides. – Fleur-de-lis rollout drawer box with UV coating. – Overall Dimensions: 19-1/4″ wide x 21-1/4″ deep x 7″ tall.