Key Switch Heads. Selector switch heads with keys have a cutout diameter of 22mm are available in 2 position. Separate key switch head units provide maximum flexibility for many possible solutions. Non illuminated To be used with a clip and electrical contact blocks Spring return, 45 ° Plastic chrome bezel Equipped with locking ring Key withdrawal position - 0 Supplied with 2 keys (profile no 455) IP66 ingress protection