Rubber nail /stick on heels .These can be cut to shape after fitting,They require a good contact rubber adhesive (not supplied) .Nails supplied.These need some degree of skill to fit.A hobby drill and disc cutter/Barrel sander are essential to fit.Available in 7 sizes:
28.5mm wide x 30mm long, 35x38mm, 41x44.5mm, 50x53mm, 58x60mm, 63x68mm