... an integral part of a pipeline system. Tianyu pipeline sight glass gives you the following features: Materials: SUS304, SUS316LCoupling modes: ... steel fittings (tee, joint with elbow, floor drain, pipeline sight mirror, gauge, flange, hose connection, cup, union, spray ball), sanitary ... , ball check, disk check), accessory items and component parts.Sight Glass ( sight mirror. food machine fitting )