It's from my S40. It's the previous version when they used double chainring instead of the single chainring in the current version of S40. The quality of the Rival crank is really nice. I think the finish is better than my Cobb crank. Too bad Sram Rival can't be made shorter.
I think you need a GXP BB to put the crank in. Robert Holler can tell you for sure what to get. Just email cruzbike support.
Michael