This mounting screw is for use with our SP-100, SP-137, SP-150 & SP-175 strike plate, armature plate or keeper plate - Zinc-Plated Steel Flat Head Phillips Machine Screw, 8-32 Thread, 3/4" Length The angular head with use in our striker plate, armature plate or keeper plate aids with facial alignment with the electromagnet to ensure good facial contact with the electromagnet maximizing holding forces.