SGN 10 3/8" FL I/U sight glass - Danfoss, OEM manufacturer part number 014L0172. Verified technical data: Product description = SGP10FN. Applications: commercial and industrial refrigeration, marine reefer plant, cold storage installations, and secondary-loop cooling. Danfoss is a leading manufacturer in this segment; the 014L0172 sits within the Danfoss refrigeration components range.