F450 TBS Discovery arm extension mounting block

Use this mounting block to attach 340 x 13mm aluminum tubes in order to extend the arms of your F450/F550 or "TBS discovery" copter.
This extension arms are able to support up to 14" propellers.
Bill of materials (each arm):
* 2 x M3 25mm screws
* 2 x M3 20mm screws
* 2 x M3 10mm screws
* 6 x M3 nuts
* 1 x M3 30mm screw
* 1 x M3 lock nut