Have a black light already? This is the perfect kit for you. Now you can forget about messy dye handling, complicated hose connections, opening and closing valves, or venting refrigerant into the atmosphere. U-View's patented SpotGun dye injection system is, quite simply, a giant leap forward in simple, easy dye injection. Simply connect it to the low or high side (even with the engine running) and squeeze the trigger. The dye is now injected into the A/C system.