Shutter works with loose contact. Error Ruhr thing are obviously two battery terminals in the receiver, which were exactly reversed. Spiral spring contact for the positive terminal (normally this is provided for the negative pole), and the "contact button" in this case for the negative terminal. The receiver is relatively large and depends on the cable next to the camera. I have returned to the remote trigger for these reasons, but would keep it because of the low price, when functioning properly.