Omega 10125B Black Hydraulic Bottle Jack - 12 Ton Capacity Hydraulic System is Protected from Internal Damage by a By-Pass Mechanism. Fabricated from Hard Cast Steel with Heat-Treated Critical Stress Areas. Machined and Polished Cylinders with Die-Cut Threads Provide Non-Abrasive Leak-Free, Durable Performance Unique Cross-Type Forged Release Valve Assures Positive Load Control Overload Protection