The PM Hoof Clips for Treating All Varieties of Horn Cracks The unique expanding and tightening mechanism, which is the core of the well proven and patented PM Hoof Clips Regular and Special, makes it possible to adjust them to the very last millimetre after mounting. According to the requirements, you can tighten the hoof crack or even expand it, if the outer lamina is trapped in the crack. With its tightening and expanding mechanism, the PM Hoof Clip is the worldwide unique method to fix and tighten a horn crack or to expand it, which is necessary, if the outer lamina is trapped in a hoof crack. There are holes in the stainless steel plates on either side of the tightening and expanding mechanism for a secure moun-ting of the PM Hoof Clip. Using these holes the PM Hoof Clip is additionally fixed to the hoof wall by provided screws, after the clip ends have been fitted in the previously milled splits in the hoof wall. This additional fixation allows an expansion of horn cracks. At the same time this improved design guarantees a long- lasting, tight-fitting PM Hoof Clip that is reusable.