The NG-4 Nitrogen Inflation system is our most affordable unit. This 4 CFM nitrogen generator uses the highest quality membrane and comes standard with an internal 60 gallon nitrogen storage tank. All TSISSG systems utilize the highest quality membranes. The benefits of nitrogen tire inflation rather than plain air have been enjoyed by Formula One, NASA, NASCAR, earthmoving equipment, US Military and Tour de France racers for years. Thanks to TSI these affordable generating systems are now available to the general public. What technically makes Nitrogen inflation so beneficial? Plain air inflated tires gradually lose pressure at up to 4 times the rate of Nitrogen. Nitrogen molecules are much heavier than air keeping your tires properly inflated 400% better. Nitrogen provides safer driving conditions and longer lasting tires due to the reduced migration. Plain air contains moisture and sometimes even oil all contributing to wheel rim rust and rubber eating oxidation. Nitrogen has NO moisture or oil so there is no corrosion of rims, inter-lining, belt, or air pressure monitoring devices. Nitrogen has reduced tire failures as much as 80% and given truckers four or more retread lives. Specifications: 39" length x 41" weight x 62" height; 625 lbs shipping weight