The Hybrid Collapsible Stock serves to break the barriers of traditional air through and air in stock systems by enabling a user to seamlessly switch between using a 13 cubic inch air cylinder or a remote line.
I purchased this item for my M17 Elite SBR build. Upon receipt, I was blown away by the build quality and overall ease of installation. The guide rails are VERY tight at first, but once you apply a bit of lube and expand/collapse the stock a few times it'll loosen up nicely. Just wish they made the tan version available for retail!
Milsig always shoots to amaze, and this is a great product. I bought it for my Para Pro, but was disappointed to find out that it will only fit on M17s, but a dremel fixed it pretty nicely. Overall its an amazing stock that works great on any M Series marker.