The FRS-15 is a nifty looking AR-15 stock designed for the California market. In California you can use pre-ban full capacity magazines, with a standard magazine release, in semi-automatic rifles which do not have a pistol grip, adjustable stock or flash suppressor. The FRS-15 does not have a pistol grip (as defined by the State of California) and is not adjustable.
The stock costs $190. The initial orders will be shipped with buffer tube covers with cheek risers (as pictured above).
[ Many thanks to Gunslinger for the tip. ]