You can find the Armaspec SMB Buffer Kit Gen3 Carbine here Fast $9.95 shipping! Orders over $200 ship for free!

The Armaspec Sound Mitigation Buffer SMB Kit includes a buffer tube, end plate, castle nut and a Gen3 Sound Mitigation Buffer. The Sound Mitigation Buffer prevents the buffer spring from rubbing against the buffer tube providing smooth, quiet operation. Made in the USA.

Buffer Weight: 3.3oz (Carbine)

The Sound Mitigation Buffer is available in 6 variations:
SMB-Carbine with a weight of 3.3oz SMB-H with a weight of 3.8oz SMB-H2 with a weight of 4.7oz SMB-H3 with a weight of 5.6oz SMB-AR10 with a weight of 4.7oz SMB-9 with a weight of 6.9oz