These silencers are specially made for use on IDP-15, SH-110 and SH-112 dry scroll pumps and that are not connected to a house exhaust system. They are designed for clean dry air (CDA) vacuum pumping applications where the exhaust is vented into the room. They greatly silence the exhaust of dry pumps. These silencers come with all the hardware to connect to the exhaust of the IDP-15, SH-110 and SH-112 Pumps.