Low profile but still very effective - ADE Advanced Optics Ultra Compact Pistol Green Laser Gun Sight

I was specifically looking for something that wouldn’t add bulk, and this laser fits that requirement perfectly because it sits low and doesn’t stick out in a way that affects handling, yet when you activate it, the beam is strong and easy to see, which is exactly the combination I wanted, and after using it for a few weeks, it’s held up well without any loosening or issues.