Side Pump Bottle Jack,4 Ton Hydraulic system is protected from internal damage by a patented by-pass mechanism. Machined and polished cylinders with die- threads provide non-abrasive leak-free, durable performance. Fabricated from hard-cast steel with heat-treated critical stress areas. Serrated heat-treated saddle provides generous lifting area and secure grip. Heat-treated extension screw allows low pick-up height adjustment and maximum lift height. U.S. Patented built-in by-pass device protects hydraulic system from overpumping damage. Unique cross-type forged release valve assures positive control. A wide, rugged base provides stability and strength. Critical stress points are reinforced in all models for added durability and dependability 10045B