Sorry, also posted in the mechanics section but haven't gotten any responses. Hoping someone here knows offhand. Thx.

SRAM has the PC1090R, PC1090, and PC1070 -- can't figure out what the differences are... My local Performance has some of them, and hoping to pick up a new chain and cassette tonight, but unsure if it makes a difference which chain. I definitely want the connecting pin, but from what I can see all three have it anyways. Anything anyone can provide would be appreciated. Thx in advance. Matt