The glass filled thermoplastic casing with cap tether holds Midi fuses which are placed on the the two internal M5 threaded studs and lock hex nut terminals. This Midi fuse box can be bolted down with the two fixing holes for security and protection and these fuse holders can be fitted neatly just about anywhere. This particular model has the added feature of being able to 'Dovetail' multiple units together & also has a viewing window.