The number of screws in the set is adjusted to the number of screws for the tank.
The resin tank screws wear very fast from unscrewing. It is difficult to unscrew them and an allen key socket is loosing shape, which makes it impossible to unscrew and replace the FEP foil. Therefore, it is worth having a set of screws that fits the Allen key, replace the screws with new ones and avoid the problem of unscrewing them.