Posing a watch/bracelet?

I am modeling a tech wearable, similar to a Fitbit. The model will be used in place of product photography for my client, so it’s important that it be accurate.

If I model it flat, so the wrist strap is open and the watch is laying down, is there a way to “close it” so that the length of the straps stays the same? Essentially I would just be posing it. I am having a difficult time explaining this, but hopefully, someone can make sense of what I’m asking.

I am just shooting in the dark here but I am not sure if doing a quick bone rigging of the strap and locking which axis you are wanting it to rotate on and then you should be able to pose the strap however you want and it won’t stretch beyond its own geometry. Not sure how many loose parts you have in the strap. You could even create a shape key of it open and flat then set it to it’s closed position and slide between it to open and close. But I am sure there is probably a better way to do it that someone else will chime in on.