They snap on pretty easily but have been secure enough not to come off in weeks of daily active wear. I was worried about them being too bulky however they are not. After a few days you don’t even notice these as being a extra part. Lastly, the entire screen is completely visible edge to edge. These add significant scratch protection for all exposed surfaces. The only area not protected is the back of that watch and that has to be that way to expose the sensors. Given the very low cost and how well these work, even if the protective glass screen gets scratched every month or two, I will just buy more and continue to use these!! I love them!