Sight Glass and Moisture Indicator provides a quick visual diagnosis of refrigerant and moisture levels within a system. The sight glass indicates if the system has the proper refrigerant level, a restricted dryer or excessive pressure-drop. The moisture indicator recognizes moisture within the system. Provides early warning that a potential failure exits resulting in corrosion, chemical damage, restricted flow, or even compressor failure. Etch-resistant glass with a simple color comparison provides easy viewing and quick diagnostics. Flare models feature forged brass body and fittings for corrosion resistance. Sweat models feature copper fittings to permit solder installation without disassembly. Leakproof design is compact and short in length to easily fit within a unit and provide accuracy in performance.