Sit-to-Stand Two-Tier Base lets you alternate between sitting and standing for a more healthy approach to work. Paired with a tabletop of appropriate size for a complete workstation that you can adjust with a programmable handset. Powerful dual motor allows synchronized and precise compensation for uneven loads. With smooth quiet movement, the steel frame base adjusts from 26.6" to 45.1" in height for 48" to 72" wide tabletops at a speed of 1.3" per second. The 21" top support bracket matches desktop that are 24" to 30" deep. Base features built-in temperature and overload sensors as well as ISP (intelligent system protection) anti-collision safety feature. Weight capacity is 275 lb. Pair with Lorell Sit-Stand 3rd-Leg Base (not included) to support your return.