Heavy-duty, professional quality, 100% USA made hydraulic bottle/ hand jacks built for service under constant use and durable enough to last a lifetime. For vehicles of all types and sizes, heavy-duty trucks, military and defense vehicles, farm equipment, building construction, emergency vehicles, and/or in conjuction with original equipment manufacturers of various products. Heavy-duty ductile iron castings for both the base and head cap of each model. Electroless nickel plated steel ram and steel pump piston prevent and protect against rust. Safety fluid bypass system prevents the user from overloading/damaging the jack so it cannot be used beyond the ASME/PASE load-limiting standard. Ram stop ring prevents ram from being overextended.