I have been wearing the Microsoft Band, size medium, for about a month. Previously, I wore a Fitbit flex, which had a simple clasp, fairly reliable. I had doubts that the clasp on the Microsoft Band would be comfortable, reliable, or strong enough. In reality, for me, the clasp is all of these things, and also easy to adjust. The spring-action latch mechanism works great, and allows for adjustments with a simple pinch and slide.