happu-store Magnetizer Demagnetizer Screwdriver Screw Bits Magnetic No batteries or electrical required, easy to use. Quickly Magnetize Or Demagnetize Screwdriver Tips Or Screw Bits Swipe The Shaft Of The Screwdriver Over The + To Magnetize Swipe It Over The - To Demagnetize Dimension: 49 x 49x 27mm