These 3/4" round x 1" long Thumb Release Knobs/Buttons are machined from high quality aluminum. The 4-40 threaded hole is offset from center for more adjustment to find that sweet spot. These are a great way to increase accuracy while giving your release a personal touch. These just slide onto your stud on your release, and tighted down with a set screw.  You will receive 1 Button/Knob with your choice of diameter: 3/4',5/8", or 1/2"(3/4" is only available at this time). Release in Picture (Stan Perfex shown) is example of what your release could look like and is not included. Our products are American Made!