Q: Im a little confused, is this an AR15 buffer and buffer spring all in one or is this only the buffer spring. I'm new to internally upgrading an AR15.
A: As stated in the product description:
-The Silent Captured Buffer Spring assembly
-One (1) captured recoil spring, pre-installed
-Spacer to allow for installation in both carbine- and rifle-length buffer tubes
In short: it's the whole thing, all in one, etc. If you need more information please contact the manufacturer directly. Thanks for the inquiry. Tactical Link