The tension acts on the bottom of the puller and the combined puller head.  In addition to the measurement method of 90° as shown in the figure, there are other methods of 45°.

Secure the lower part of the bite zipper and pullthe pull head up.

Lock the puller head in the middle of the teethand pull the chains eft and riaht in their
respective directions.

Stretch the bite zipper horizontally atconstant speed.

Pull the pull head to the bottom, separating thetwo chains left and right and pulling in their
respective directions.

Lock the puller head in the middle of the teethand pull the chains left and right in theirrespective directions.