Refrigerant Leak Detection Kit, Typical Application Air Conditioning and Refrigerant Leak Detection, Amount of Oil in System Up to 4 Gal, Amount of Refrigerant Up to 50 Lbs, Dye Type Universal, Type of Compressor Oil Polyol Ester, Alkyl Benzene, or Mineral, Includes OPTIMAX (Rechargeable) Inspection Lamp, EZ-Ject Dye Injector, 2 EZ-Ject Cartridges, Fluorescence-enhancing Spectacles, GLO-AWAY Cleaner, Perge Fitting, AC Charger, DC Charger, Plastic Carrying Case and Instructions
The best way to test any level is to swap it end for end. you should get the same reading. If you are reading 1/4 bubble high on the left side and you flip leve, you should still read 1/4 bubble high on the left. if not the level is off.