These Locking T-Nuts are a game changer. No need to mess about fishing around trying to place the T-Nuts in the correct position in your foil box. Put them in position once, tigthen up the M4 grub screw, and away you go. 

Note that the M4 locking screw does not need to be done up tight. It holds the track nut in position, so just tighten enough to lock it in place. If you over tighten it could damage your board.

4 LOCKING T-NUTS IN A BAG