Jamesvm

Please can someone help me!! I’m fairly confident my X5 has a sub in it which I think is much needed but looking in the storage locker with the fuses I’ve found this plug. Now I think it went to a sub but it’s only 5 pins? All the ones I can see for sale all seem to have a completely different connector to then that don’t look like they’ll fit? Has anyone seen a sub connector like this before? And if so do you know which brand of sub it fits? Cheers, James