MS3180 & MS3181 Plug & Receptacle Dust Caps Amphenol Pcd MS3180 & MS3181 Plug and Receptacle Dust Caps are Qualified Products List (QPL) approved. The MS3180 dust cover plugs and the MS3181 receptacle dust caps are available with different end link options. The plug and caps are available in wide variants based on the shell size, class, and length.