I have a used Geiselle trigger that was in a used 6920 I bought. Also a JP AR Speed Hammer, can be bought with the Geiselle or separate. The package for the speed hammer says "for .169 Colt receivers" referring to the pin size. Obviously the Geiselle is for that size too as they both came out of the same rifle. They look to be in excellent shape. I really have no idea what these parts are worth, some quick Google searching for the price just found me some articles about how great these triggers are and how they're not in stock anywhere. I'm going to say $300 or best offer for both, with a big emphasis on best offer because after a couple of emails I'll average the offers to give me a better idea of what they're worth and take one of the higher ones. Thanks.
Edit: I don't know which model Geiselle trigger this is, it has two set hex head screws, one in the front of the trigger, one to the rear of the trigger.