Spike's Tactical AR-15 carbine receiver-extension kit. It includes the buffer tube and the hardware to mount a stock, but no stock itself — pair it with a separate mil-spec carbine stock.

Features:

• 6-position 7075-T6 mil-spec carbine buffer tube, laser-engraved position marks
• Spike's ST-T2 tungsten heavy carbine buffer
• Carbine action spring
• Castle nut and end plate
• No stock included

The ST-T2 buffer is heavier than a standard carbine buffer, which makes it useful for tuning recoil and cycling. Pair with any mil-spec carbine stock to complete the assembly.