SG are sight glasses for commercial refrigeration applications. They are made in brass and are available in
versions with flare, solder, face seal or socket connections.
The SG and SGR are mainly used to indicate the condition of the refrigerant as well as the liquid level in
the receiver or the oil level in the compressor.
The SGI/SGN and SGRI/SGRN are equipped with sensitive indicators that change colour depending on
the moisture content in the refrigerant.