It comes with a lanyard with a lobster claw. You can get small split rings in the fishing section of any store with a outdoors section. I favor using swivel snaps for smaller items. The arts and crafts aisle of Hobby Lobby or Micheal's is also a good place for regular snaps. Paracord is sold in a multitude of places, both online and in sporting goods and army surplus stores.
I carry mine in a holster, Ripoffs CO-192. It fits the Fenix holsters well also.
For the keyring I have the Fenix E01 which replaced the LOD CE which kept coming on or coming apart in my pocket, hasn't happened one time with the E01.
do you save any money if you buy the trit and slotted piston seperately and then glue it in yourself? Can you trade in your old piston and save some money?