If you're looking for the HK416-C stock, there are two versions made by AABB available at EB Airsoft. One is for the 416C GBB whilst the second should be popular amongst AEG owners as this one's made for the 416 or M4 AEGs. For some custom work, you can convert your existing M4 or 416 with a compact and telescopic stock for that M4 AEG pistolised version.