This project allows switching any of four male audio 3.5 mm inputs to one 3.5mm output. It uses a 2"x2"x1.5"flanged potting box allowing surface mounting. I use it to switch between my Ipod's and Sirus radio to the remote input on a car CD player. The project has been in use for several years and all parts but the box are available from Jameco. I have the schematic, parts list and a few pictures if anyone is interested.