This is a Neo Geo Pocket with a dedicated adapter.

I haven’t been able to confirm if it reads games because I don’t have any, but the monitor is in good condition after initialization, etc.
I was able to adjust the monitor and volume.

The battery and adapter are working.

As shown in the photos, the thin battery (button battery) part is worn down, but it can still be used.
Otherwise, the condition is good.

Product Information