Does anyone know what kind of adapter this is?

[Mixin67]

I have a lot of fish tanks but have one in particular with a strange light fixture on it. A while back I lost the power cord for it but not the light, this adaptor is connected to the light and is what connects it to the power brick which plugs into a socket. I’d like to order a replacement of some kind but have no idea what to look for. Any help would be appreciated.

 

[DPG]

Looks like what we over here call a barrel connector or DC connector. Usually wired with the positive to the centre pin but some manufacturers like to keep us on our toes by doing it the other way around!

 

[Mixin67]

Looks like what we over here call a barrel connector or DC connector. Usually wired with the positive to the centre pin but some manufacturers like to keep us on our toes by doing it the other way around!

Thank you so much, this has been bugging me for weeks!

 

[freddo]

They come in a large number of sizes, the most common is 2.1mm.