Extending power cable for BT Mini Disc, 2.5 or 2.1mm?

[portlanders1]

I have my router on top of a cabinet and the cable length for the BT Mini Wifi Disc isn't long enough, so i wish to extend this. 

Can anyone tell me if the plug size is 2.1mm or 2.5mm please?
I can't see it mentioned anywhere and don't have the instrument to measure such a small amount.

I'm thinking of using a 5.5 x 2.5mm (or 2.1mm) DC Power Plug to Socket Extension Lead Cable 1.5m

Thank you for any help. 

[Anonymous]

The wholehome discs are 2.5mm, I assume the Premium WHW and the black discs are as well.

[portlanders1 · Accepted solution]

To confirm for any future reference the sizing for the BT Wifi Mini Disc is 5.5 x 2.1mm.