"This Blackhawk Automotive manual hydraulic jack is protected from internal damage by patented bypass mechanism. Machined and polished cylinders with die-cut threads provide nonabrasive leak-free durable performance. Pistons qty. 1, Min. Lift Height in. 19 3/8, Lift Capacity tons 4, Max. Lift Height in. 34 3/4, Base L x W in. 5 1/8 x 4 1/2. Fabricated from hard-cast steel with heat-treated critical stress areas Unique cross-type forged release valve assures positive control Wide, rugged base for strength and stability"