The KWA QRF Mod 2 is a fantastic rifle, but the stock is lacking space to fit that majority of batteries in there...
Enter the Project Airsoft KWA QRF Mod 2 Battery Extension Unit
This Battery Extension Unit increases the battery storage area by 43mm which may not sound like much, but that's over 30% extra space for you to fit in the battery of your choosing.
It fits and clips into place just like the original cap which comes with the rif and does not effect your usage of the rif at all (except now you can use the batteries you want!).
Note: Available in Tan or Black. Shade of colour may vary.