SR 450 Single Stage Heavy Duty Regulator, Acetylene, 2 psi to 15 psi Delivery, 3,000 psi Inlet ORS NASCO Hydrates with electrolytes that help Hydrates with electrolytes that help them replace the carbs Wider knurl for easier adjustment Laser etched scale provides a quick and convenient way to determine fastener size in either SAE or metric Wide capacity jaw provides versatility to accommodate a greater size range of fasteners Wider handle provides more comfort and less hand fatigue Medium to high gas service capacity Single stage design Stem type seat mechanism Delrin® cap bushing for smooth adjustments External self reseating relief valve not designed to protect downstream apparatus