US adapter/specs for PiHub

Hope you don’t mind my asking about an older product: I bought a PiHub in the UK a couple of years back now, but I’ve moved to the US in the interim and don’t have a suitable adapter. I’ve tried out a number of replacements but haven’t been able to find one with a connector that fits, so I was wondering firstly what the exact barrel/connector size I need to be looking for is, and if at all possible, whether there is anywhere I could still get either an original US adapter or an appropriate/approved alternative - my adapter collection is rapidly expanding and I’d rather not add more to it if I can help it!