The Trinity Force SBA Recoil Spring is a drop-in buffer system designed to help the AR-15 platform function more smoothly and quieter. The carefully balanced, all-in-one system is easy to install and quickly reduces friction and vibration with much smoother harmonics than traditional buffer systems. Fits M4-style buffer tubes for AR-15 semi-automatic rifles.
MSRP is $29.50 at trinityforce.com