STP? R-1234yf Advanced Auto Air-Con Recharge Professional Formula Refrigerant + PAG Oil & UV Dye helps replace refrigerant and oil from your A/C system and contains UV dye to assist with detecting and locating leaks in metal and rubber components. STP? R-1234yf Advanced Auto Air-Con Recharge is designed to work with A/C PRO CERTYF102 R-1234yf Gauge and Hose only (included in this kit). Features & Benefits: Replaces refrigerant and oil lost by your A/C system to restore cold air. Helps extend A/C system life by replenishing lost lubricant. Contains UV dye to help detect leaks in metal and rubber. components Topping up is fast and easy - can be done in as little as 10 minutes. Not suitable for hybrid vehicles and vehicles requiring R134A regrigerant