For low pressure applications (Max Working Pressure 35 bar/508 psig), Danfoss produces and markets sight glasses types SGR, SGI and SGN. They are available in versions optimized for refrigerants with mineral oil, e.g. HCFC, and in versions optimized for non-flammable HFC refrigerants, with flare, solder, face seal or socket connections, and with and without moisture indicators.