Those are the little things than can make (our break) your foil session. So it should be a no brainer. Most foilboards are using US Twin Tracks and there is nothing that really prevents the T-Nuts for slipping out of the tracks when not attached to your foil, meaning it’s quite easy to lose them and drive you crazy if you have no spare.
Since F-One started to ship those little rubber track stopper with our Slim Tech foilboards, we have used them everywhere else (Rocket Wing, Rocket SUP, Rocket Surf) and now we are packaging them in set of 2 as accessories. You can get them here.