Guitar pedal

This guitar pedal doesn’t connect to my power supply like my other pedals. What’s going on with this pedal.

supposedly theres a flip out panel on the top for a 9v battery but the middle input on the lhs should be a 9v feed?

Yea that’s the thing it say 10volt

And it does have a front flip for battery

It’s designed to use with a 10/11v supply.

But it apparently works with a 9v supply.

STREO Flanger pedals in guitar and / or low
four pottards delay, width, speed and regen
Jack connector and 10v power supply (works with 9v power supply with reverse polarity)
solid as a tank …

It makes sense that a 9V power supply would work since it can run on a 9V battery.