Mersen semiconductor fuse blocks feature open face styles. Each version is rated 750 volts and accommodates 14 x 51mm or 22 x 58mm IEC cylindrical fuses. 703, U705 and U710 fuseholders feature Mersen's unique adder-block design which can be assembled onto 1, 2, or 3-pole fuseholders to form multi-pole segmented holders of as many poles as desired. A choice of box, screw, or pressure plate connectors is offered to fit a wide range of standard or solid copper wire. All versions have verified dielectric strength in excess of 2500V. A patented built-in DIN-rail adapter on the U710 blocks adds further design versatility. All fuse clips are made of high conductivity tin-plated copper with spring reinforced clips.