Kynshot hydraulic buffer ar-10 w/coll stock 308 3.25" buffer FEATURES-Reduces felt recoil 20-30%-Replaces buffers that are 3.25" in length-High strength 17-4 stainless steel construction-Military grade materials & processes used in manufacture-Designed for 7.62mm/.308 cal. AT style rifles with AR-10 length collapsible stock tube (3/4" longer than an AR-15 stock tube)-Works with Armalite, SigSauer, Noveske, & LWRCI .308 rifles with collapsible stocks & any others that use the collapsible stock tube Other Features: Replaces 308 buffers that are 3.25" in length.For ar 308 rifles wtih an ar-10 length collapsible stock tube which is 3/4" longer than an ar tube not compatable with ar 308 rifles that use a standard ar-15 buffer tube.