Under-Saddle Tag Mount
Remove contents from packaging
Place your device in the centre of the mount and then close the lid and secure from the underside using a 20mm bolt
That is then offered to saddle rails and it should be fitted facing the rear of the bike on top of the rails.
Place the small block under the rails to meet the mount and you then have a choice of 20mm or 30mm bolts (secure bolts are only 30mm in length) to screw through the two visible holes. This action will secure the top and bottom either side of the saddle rails.
The bolts should be tight enough to stop movement which is sufficient for everyday use.