The hardest part of adding a subwoofer is the installation and connection of the amplifier, with our new Rapid-Fit wiring kits the process is made very simple indeed. The Rapid-Fit kits allow the installation of power direct from the interior vehicle fuse box and high level signal input to the POWERBOX400.1M-V7 directly from the factory head unit so there is no need to run power cables through the vehicle firewall / bulkhead. The kit features a fused spur for “Rapid Fit” power installation into vehicles internal fuse box and unique wire clip connectors for fast and easy connection to speaker wires for high level amplifier input.