The stealth recoil spring SRS Gen 4 offers a hassle-free upgrade, serving as a self contained multi-stage replacement for the standard buffer and spring in your firearm. With its innovative design, the SRS ensures a seamless, noise-free operation by preventing the buffer spring from rubbing against the inner buffer tube wall. Moreover, the second stage of this recoil spring significantly reduces felt recoil, enhancing shooting comfort. This AR-15 kit is conveniently pre-assembled as a c configuration and includes both an h and h2 weight, allowing you to fine tune it according to your specific needs. To enhance durability and eliminate potential failure points, we have replaced the screw with a roll pin in the plastic end piece, and the cap is meticulously machined on the rod. Additionally, the traditional snap ring has been replaced with a washer for improved reliability.