Height-Adjustable T-Arms for Volt Series Task Chairs, Black. Optional height-adjustable T-Arms reduce strain on neck and shoulders. Made of plastic injection molding and urethane arm pad they add support to existing chair. For Volt™ Series Chairs. Color: Black; For Use With: HON® Volt® Series Task Chairs; Series Name: HON® Volt® Series; Arm Style: T-Arm.