This 4.5lb 2-stage National Match trigger kit is for a stripped lower which does not already have a lower parts kit installed. Our Rock River trigger kit with 2Stage NM trigger includes all pins, springs, and parts to assemble a stripped AR-15 lower receiver with the upgraded 2-stage RRA trigger. This product retails for $180-$200 (upgraded grips) from RRA.

This National Match two-stage trigger from RRA is an excellent trigger for your AR15 rifle. These are used frequently in Varmint and Long Range AR builds where a lighter 2-Stage trigger really helps accuracy and round placement. These triggers come pre-adjusted by Rock River gunsmiths as a matched pair and drop in all mil-spec lowers with no adjustment necessary for an easy drop-in install. Rock River 2-stage NM pins are .1555 in diameter and are not recommended or designed to be used with .154 pins or .170 Colt lower receivers.  .1555 RRA Trigger pins will install in any standard milspec lower receiver without modification but may be noticeably more snug than the .154 pins upon install. 

Can also be used in conjunction with JP reduced power springs for an even lighter pull weight:
http://www.joeboboutfitters.com/JP_AR_15_REDUCED_POWER_SPRING_KIT_p/jp-jps3.5.htm

RRA-AR0120NM-Rock River Lower Receiver Parts Kit, Two Stage Trigger, A2 Grip Black $180 MSRP
RRA-AR0120NMH-Rock River Lower Receiver Parts Kit, Two Stage Trigger, Hogue Black Grip $200 MSRP
RRA-AR0120NME-Rock River Lower Receiver Parts Kit, Two Stage Trigger, Ergo 4005 Ambi Black Grip $200 MSRP (includes gapper)
RRA-AR0120NMET-Rock River Lower Receiver Parts Kit, Two Stage Trigger, Ergo Tactical Grip w/ Palm-shelf (235 MSRP)

Note: Most of the new incoming stock on the Ergo grip kits do not include the bottom grip plug