Type S magnetic contactors and starters are for motor control applications and 8903S lighting contactors are for lighting control applications. This On Off selector switch kit is for NEMA size 00 through 3 Type S contactors and starters or 8903SM or 8903SP lighting contactors in NEMA 1 enclosure. The selector switch is mounted into the knockout in the enclosure cover. This selector switch kit is UL listed and CSA certified.