Type S magnetic contactors and starters are for motor control applications. The control circuit fuse holder is for use on Type S contactors and starters, when one or two control circuit fuses =600 V are required. This fuseholder will work on Type S contactors and starteres from NEMA Size 00 through 7. Type SF4 fuse holders will accept standard 600 V Bussmann® Type KTK or equivalent fuses (13/32 x 1-1/2) up to 6A maximum. This fusehlder is designed to hold two fuses. The fuseholder is UL Listed and UL Component Recognized.