Komplete Kontrol S88 power supply socket size?

Blah-Bloh

Hello,

I would like to buy a small cable extension for the power supply of my S88 Mk2. The reason is that I have to plug and unplug the keyboard every time I use it and I fear it will prematurely damage it and I sure don't have the skill to replace the port myself.

So my question is what is the size I should be looking for so it plugs correctly?

Thanks