The handle comes with two fixing points each with an individual plate, these are fitted to wooden and timber doors using three screws. The handle then attaches to the plates and is secured with the Allen bolts. The internal fixings are not visible on the door.
The bolt through method uses a brass thread reducer; this is included in one of the two accessory kits. The brass thread reducer has a 1.5mm thread on the outside which will thread into the upstand. On the internal of the reducer is an M8, this is an 8mm bolt through which provides an ideal position for an internal bolt to fit through.
The two Allen bolts give extra protection against vibrations that may take effect on a main road causing bolts to come undone. With the Allen bolts this will not happen.
This system is incredibly easy to use and will reduce fitting times to just seconds. Included in the second accessory kit is two plates which have holes all the way through, once the plate is fitted on the inside of the door, the bolt can be pushed through the plate and screwed into the brass reducer. The internal handle would then be fitted using the hidden fix system. This offers an extremely strong back to fixing method.