I got a gxcs4i refurb from fleabay. Hopefully that dont bite me in the rear. When it arived it looked as new as new can get. It made dead head test to 300 bar in 27 seconds and has worked flawlessly since. I bought a dual temp sensor, led lights, and an hour meter. I wanted to do as little structural mod to the case. I did drill a half inch hole in the back for wire access then installed a rubber grommet. Blue temp for h2o tank red for compressor head. Wood frame a saddle and enough wire length to easilt remove and also a filter added