This Grass Polygraph EEG 79WU8G Ink Writing Osciliscope Chart Recorder comes from a working install. Obviously, the ink is dry and the ink paths need to be cleaned by the buyer, but the pens move and the paper advances properly. We warrant that level of operation for 60 days from purchase. PLEASE BE AWARE, YOU ARE GOING TO HAVE TO CLEAN THE INK PATHS UPON DELIVERY!