Gelish ProBond is a gentle acid-free preparation product for the natural nail. It will promote adhesion of acrylics & gels to the natural nail. ProBond has a neutral PH with the use of ethyl acetate making it acid-free. Creates a bond to the keratin in the nail to give complete adhesion to the nail plate. ProBond Nail Primer works with gel polish and nail lacquers. Like double-sided tape, a bond is created when a primer molecule links one “arm” with the molecules in the nail and the other arm with the molecules in the product.