Rubber straps fits the best. On my 616 i very rarely wear a blue strap. See the 616 thread. If leather u could have a look for a black one with white stitching or something in grey . I would stick to the rubber
.....you're incorrect. The Black Knight is the PAM317. That is due to the black ceramic and the black movements. I'm afraid you'll have to come up with another...moniker for your 616 Credit for the pictures, obtained on the Web: Bidle.