Mersen UltraSafe Modular 600 Volt Fuse Holders for Class J fuses introduce a new level of safety and ease for installing or replacing Class J fuses. UltraSafe holders qualify as “finger-safe" to an IP20 grade of protection under IEC standards. The US3J accommodates 30 A Class J or 22 x 58 mm French Ferrule* fuses. The US6J is for 60 A Class J fuses. UltraSafe holders are available in compact 1, 2, or 3-pole units, with or without blown-fuse indicators in each-pole. Multi-pole units can also be made up in the field by using the multiple pole Assembly Kits. All units have provisions for locking in the open position for safety during fuse change outs or equipment servicing. US3J and US6J holders can be snap-mounted to 35 mm DIN-rail and they have a unique latch which will stay open to allow re-positioning of the holder in the future. UltraSafe body material is tough and durable polyamide. *Holder not UL listed when installed with French Ferrule fuses. RECOMMENDED FUSE USAGE: *US3J, US6J use with AJT, A4J, HSJ.