Magpul MAG482-GRY UBR Gen2 Stock Collapsible Stealth Gray Synthetic for AR-15, M16, M4The UBR GEN2 is an adjustable stock for AR15 M4 and AR10 SR25 platforms, designed to offer similar strength and stability as a fixed stock with a consistent and comfortable cheek weld in any position. An update of the revolutionary Utility Battle Rifle (UBR) stock, the UBR GEN2 features a fixed cheek piece to provide a consistent cheek weld in any of its eight positions and is compatible with Carbine as well as A5 and SR 25 length buffer systems.