NSN:
Center lit reticle, amber, NV compatible
Backup irons, tritium dot in front sight, rear ghost ring
Has the TA51 flat top mount
TA01
Full line lit reticle, red.
The NSN's backup irons are pretty useless, the front blade all seems to be off center out of the factory. The TA51 mount is sturdy but a QD mount like LaRue's or ARMS 19 and 19S will be better.
Speaking of the 19S, last weekend I saw one with longtitudinal movement when the lever is swung closed. Tried it on an MRP and KAC FF RAS MRE with the same result, that was the first time I ever had first person experience with a loose ARMS mount