Active Workstation Legs: Designed for DIY tables, this ergonomic standing desk frame gives you the height adjustment you want with customization options (table top must be purchased separately). Compatibility: Recommended Table Top Sizes - Length of 40 to 77, Width of 23 to 43, and a Thickness of 3/4 and greater (Actual Frame Length: 40 to 57.3, Frame Height: 28.5 to 47.3).