The 331 Foot Operated Hydraulic Pump Stool with Twin Surgery Arms and Backrest is  premier line of foot-operated hydraulic seating. This stool offers an adjustable ergonomic backrest and vertically adjustable arms, which swing inward and outward. The smooth foot-operated hydraulic pump provides up and down adjustments of the seat height from 20.5”-28” (52-71 cm) without ever getting off the stool. This adjustment helps provide sterile and precise positioning to your most comfortable working position. Single wheel hard rubber casters make it easy to maneuver quietly over all types of surfaces without damaging or marring the floor. Treat yourself to a soft and supportive seat with premium line of seating.