A-2L swivel weaver mountable tactical swivel for small arms.

This part employs BASIS. a proprietary M-LOCK(tm) like attachment system developed by ZenitCo. Though similar to M-LOCK(tm), BASIS is not compatible. Arguably, BASIS is more reliable than M-LOCK(tm). BASIS virtually guarantees the absence of wobble and the repeatability of the "zero" once the part removed and subsequently returned back in its place. There are multiple parts that can be installed directly on to this hand guard using BASIS. These parts are:

B-30U

B-10U; B-10L

B-21U; B-21L

B-20U; B-20L

SPORT-1;2;3;4;5;6

and some others