This design is for my fiancÃÂ© who likes to run while holding her iPod in her hand (leading to the inevitable falling and shattering that you may be able to see on the screen). I'm hoping this wristband will help avoid that. This one is printed all at once and snaps together. There is no single clasp: each joint is equally detachable, but they snap apart perpendicular to the band, so it's still secure on your wrist.
What I've noticed about snap-fit joints is that they always come out a little differently on different printers. Therefore this one is customizable to different tolerances, as well as different band width, thickness, etc. This one is also oriented differently than most, giving a more secure mount.
Print it as is, or open the Customizer app to tweak it as you see fit. The length parameter is the circumference of your wrist, though you can always make it too long. You can just snap off a few segments to make it shorter. By inputting your build platform's x-dimension, it will automatically break the band into pieces such that it all fits.
This might be a good OpenSCAD script to look at if you want to learn about designing for Customizer, as it's much simpler than most of my designs, but includes some fun features.