Helmets shall consist of a rigid platform on which the appropriate head-form for the helmet under test can be fixed. A chin-piece corresponding to the body structure of the chin shall be fixed vertically below the head-form such that the chin-strap can be fastened over it. The other end of the chin-piece shall be connected to a spring balance through a chain. The spring balance shall be mounted on a moveable base, which can be moved manually by rotating a handle, which moves a screw to apply tension on the chain-straps.