Works on Cars, boats, RVs and more for Power Splitting. Removable Clear Plastic Protective shell. Will fit upto the following wire size: 1X 1/0AWG and 2X 4AWG. Hole sizes are as follows: Input = 12.5mm / Each output = 10.5mm. Solid Metal construction for safe power transfer. Gold Plated for best conduction. Course threaded gold plated grub screws to solidly secure wires