The 34970 AIR-VAC is a Venturi-type vacuum pump powered by compressed air and designed for mobile air conditioning service. Economical – easy to use, unique design uses shop air to pull a vacuum. Low maintenance – no moving parts or oil to replace. Rugged Lexan case – oil and scratch-resistant, comes with a convenient handle. Includes both 1/4" MFL and 1/2" Acme fittings. The pump has an air consumption of 4.2 SCFM and will pull a vacuum up to 29.7 inches of mercury at sea level. Oil or water in the air line will not harm the pump; it will be exhausted through the pump.