Geissele Automatics 05495H2 Super 42 H2 Buffer, Braided Wire Spring for AR-15. The Geissele Super 42 Spring uses three independent strands of wire to act as a harmonic damper and energy absorber, reducing spring failure and improving reliability. It provides a 15% stronger average return force than a standard buffer spring and is designed for use with Carbine length buffer tubes. Not compatible with rifle length or A5 buffer tubes/receiver extensions.