Outfit your classroom with this comfortable and ergonomically contoured chair. Zuma's versatile Keyboarder perfectly complements an array of task-related settings. Quick Ship Color Combinations for Model VIRZTASK18 only: Black or Navy seat with Char Black base. Product Details: Adjustable gas cylinder for 14" to 17" (ZTASK15) or 16" to 20 1/2" (ZTASK18) seat height. 5 dual-wheel caster base - 2" hooded casters (for use on both carpeted and non-carpeted floors). Flexible polypropylene shell with waterfall edge. Gentle lumbar swell on back for lower back support. Frame is constructed from 8 and 12 gauge steel. Contoured wrap around flexible ribs on seat to allow easier upper back movement.