Game Boy Color/Pocket/Light USB cable designed by Lab fifteen.
The cable drops the 5V USB voltage down to roughly 3.2v this is very close to the supply of 2 AA batteries (1.6v each = 3.2v)
The lead has a Male USB 2.0 plug one end and a 2.5mm straight DC barrel jack the other.
They are 1m/1000mm long or 39.5" to the imperial folks approx
This cable is the same for Game Boy Color, Game Boy Pocket and Game Boy Light consoles