Mersen Ferraz 303 Series midget open-style fuse blocks are suitable for mounting and securing midget fuses in a circuit. They feature an open-style design that allows easy insertion and removal of fuses during maintenance and repair purposes. These fuse blocks have a screw mount or DIN rail installation options to provide a secure & reliable connection and ensuring the fuse block remains in place during operation. They also feature a unique adder block design that can be easily snapped together to create multi-pole segmented blocks for accommodating as many poles as possible. These UL-listed fuses have a GFPC (glass-filled polycarbonate) construction for mechanical strength, electrical insulation and excellent heat resistance.