Sub-Zero? synthetic refrigerant kit has a specially designed formula featuring Cool Boost? technology that helps a vehicle's A/C produce colder air. The approximately 17 oz of R-134a and 1 oz of additives are used to recharge a vehicle's A/C system, seal common leaks in rubber components and help extend the A/C system's life by eliminating acid and moisture buildup. This Sub-Zero kit comes with a reusable charging hose and gauge.