A simple to use device to attach to a 300mm/12 inch rule to mark the centre hole spacing to mount power boards, chargers or other things you want to mount on a wall. Just loosen the lock screws, put the points of the marker into the mounting holes and tighten the screws. Place the hole marker against the wall where you want to mount your device. Use the spirit lever to make sure your holes are horizontal and just use a pencil or maker in the holes and you have a perfectly marked pair of holes.

 The spirit level was a purchase off Temu and you need 3 5mm socket head screws for the locks.The star knobsare not necessary but look good and make it easier to lock.

 I suggest using supports and print the way as shown in the photos.

Of course you also need a 12"/300mm steel rule.