Fitted to all Defenders from 1999 TD5 to end of production in 2015, as well as the D2 from 1999 to 2005
It's used by the 12N 7-pin socket kit for all of the trailer's road lighting.
Additionally, it has a permanent live and reversing lights circuits in it, which are use for the 12S 7-pin socket kit, as well as the the EU 13-pin socket kit.
The 12S kit requires the 12N kit to be fitted.
The EU kit plugs-in to this connector for road lighting.
Both the 12S and EU kit require additional connections via a VSS and relays in the vehicle's battery box.
The genuine Land Rover kits are a little more expensive, but the quality, is way ahead of the ones offered by Br(Sh)itpart.