Mersen UltraSafe modular 600 volt fuse holders for Class J fuses. A new level of safety and simplicity when installing or replacing Class J fuses. UltraSafe holders are finger safe to IEC standards and meet IP20 protection. US3J can be used for all Class J fuses 22 x 58mm up to 30A. US6J can be used for 60A Class J fuses. UltraSafe holders are available in compact 1, 2 or 3 pole units with or without a fuse indicator in each pole. Multipole devices can also be used in the field with the multipole kits. All devices can be locked in the open position for safety when changing fuses or servicing equipment. US3J and US6J can be mounted on 35mm DIN rails. The base body is made of tough and durable polyamide. Holder is not UL listed when installed with cylindrical fuses.