Spencer Oliphantwrote a review of Peak Design Micro Anchor - 4-Pack on February 20, 2018
I believe all Peak Designs products that work with these anchors come with at least enough to use. And as much as I've used mine, I have yet to need to replace them.
As already mentioned in other reviews, this is the most brilliant method for attaching a camera strap to a camera. What's better is that it disconnects easily (not accidentally) as well so I can change from neck strap to wrist strap without much thought.
These attach to your camera at the same points you'd attach any other camera strap. They just alleviate a lot of headaches.