The Big Dog II fuse block. Has three inputs (battery positive, ignition positive(from a ignition relay or heavy duty ignition switch) and ground). They get distributed to the corresponding outputs. The battery positive and ignition positives outputs are all fused via the row of mini blade fuses (25amp max fuse). This allows you to have a small, compact power center to wire up many different electrical items. Fuses NOT included. Fork terminals for the output strips are included. It is 5.5"L x 2"W x 1"H. The battery power side can handle up 75 amps and the Ignition power side can handle up to 75 amps. Not recommended for big items like big fans and fuel pumps.