A larger off-load valve boosts performance on 750 Series pumps from Wallenstein Vacuum Pumps - Elmira Machine Industries. They have 422 cfm airflow at 1,200 rpm and vacuum up to 28 inches Hg. Cooling options include air cooling (fan); liquid cooling (jacketed housing); or dual cooling, where air injection is combined with liquid cooling. Lubrication options include a shaft-driven oil pump or an automatic air pressure system that force lubricates with no moving parts. They have extra thick and wide vanes for longer service life. A standard flush port allows routine internal cleaning. A quick-access end plate allows easy internal inspection with no bearings to pull. 800/801-6663; www.wallenstein.com.