Excellent method for adding refrigerant oil or large amounts of UV leakdetection dye to the A/C system. Add oil by allowing vacuum to pull it in after the evacuation process, or use refrigerant to push it in using the recharge system. Rugged all metal 2 oz canister. The standard model uses a needle style valve attached between the manifold gauge set or charging equipment and A/C hose. 1/4" Flare Fittings for Automotive R-12 Hose connections.