These silencers are for use on dry scroll pumps and dry rotary lobe vacuum pumps that are not connected to a house exhaust system. Such as Edwards XDS35i, Varian Agilent Tri Scroll 600, Kashiyama Neo Dry 36C and Alcatel ACP 28, ACP 28G, ACP 40, ACP 40G. 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 and come with replaceable internal filter media. These media filters provide exhaust filtration to capture tip seal dust that is produced in dry scroll pumps. These exhaust silencers are equipment with an NW-25 (KF-25) vacuum flange and are rated for use up to 23 CFM. They come with a KF25 vacuum clamp and centering ring for easy installation. Also inside is a paper filter element. A replacement paper filter element is available on this website.