I have a black SMP that I've been wearing on the integrated rubber strap for about 4-5 years now. I changed over to the bracelet the other day and noticed some marking on the caseback where the strap has a small step that keeps it in place. The marks are the exact shape and placement of this 'step', and may, I guess, be the result of the very minimal movement with some dirt / debris or even sand between the rubber and the steel. I can't get pics that show it well so haven't bothered, but wondered if anyone else has experienced this? The marks are very visual, but must be fine as I can't feel anything when I run my finger over them.