The #100 Snow Guard has been one of the most popular models for decades. They are made as a retrofit application where the existing roofing material does not need to be removed. The bar on the snow guard is slotted to easily hook on the roofing nail. The #100 snow guard has eliminated the necessity of removing any slates or tiles avoiding the possibility of breakage. Simply insert the slotted bar under the slate, engage a nail with one of the conveniently placed slots and pull down to fully secure bar.