These weld-type sight glass fittings, complete with glass disc, seal gasket, and cushion gasket bolted between circular flanges, is the low-pressure version of the DIN28120. The units can be combined with Lumiglas luminaires, such as the USL06-Ex, USL07-Ex or USL08-Ex , for use in hazardous areas. Under all normal working conditions, light options include USL01 , USL13 , USL15 , USL05 , USL06 , or USL07 . For an integral light/sight glass, combine the low pressure unit and LumiStar light. Options include sight glass wipers type SW I .