The Geissele Super 42 Braided Wire Buffer Spring and Buffer Combo was designed to improve the function and reliability of your AR-15 pattern rifle. The unique spring design of these AR15 Buffer Springs uses three independent strands of wire, just like the German MG42 Machine Gun. This concept acts as a harmonic damper and energy absorber by allowing the springs to flex separately from each other. This flex helps displace excess energy which decreases the chance of spring failure and assists with making your AR-15 more reliable. Compared to the stock spring, the Geissele Super 42 Braided Wire Buffer Spring and Buffer Combo has a decreased tendency to lose length and force over a given round count. As an added bonus, it removes the annoying spring reverberations (twang) heard and felt by the shooter through the buttstock. The Super 42 Braided Wire Buffer Spring and Buffer Combo has a 15% stronger average return force than the standard buffer spring. This will assist in stripping rounds out of the magazine when operating with a dirty weapon or when using steel-case ammo. NOTE: The Super 42 is for use with Carbine length buffer tubes and is not compatible with rifle length or A5 buffer tubes/receiver extensions. We do not recommend the Super 42 with 300 Blackout subsonic ammunition. The Super 42 Spring may be too powerful and not allow the rifle to function properly. Specifications for Geissele Super 42 Braided Wire Buffer Spring and Buffer Combo: Manufacturer: Geissele Color: Black Gun Model: AR-15 Condition: New Country of Origin: USA Package Contents: Geissele Super 42 Braided Wire Buffer Spring and Buffer Combo