Is that a balsa reinforcement for the control horn mount?If so you really should use hardwood on all control horn mounts,especially with those type of horns.I use Rocket City horns,which are basiclly the same,and they will wobble and come loose in balsa.You should use hardwood,and drill and tap it so that the horn screws into the hardpoint.I also use epoxy when screwing them in.Just my.02.If it is hardwood,disregard this post,LOL.
Mike