the finer the peep the more clear the sights and target.
great for sighting in a hunting rilfe, or punching paper... just remove them for hunting, or buy a bigger one...
I have some fine ones for the williams et al, and it is amazing, with my eyes, what I can see.
I show the guys at work, but taking a piece of dark tablet backing, and push a fine thumbtack through it.
take a staple, and tape it pointy ends up on the end of a yard stick
cut the peep out rectangular, bend it 90deg and tape it on the other end, then tell them to look through the hole, at the staple, then pick a target.
When you get the hole right, the staple leg AND target are in focus!
I work in an airport tower cab, so we can pick targets some distance way.
it is absolutely amazing!