TargetTalk

I saw this for $25.00. Four iris sizes, two blinders and sideshields.
Clips on your glasses. Any user opinions on this device?
Looked at a single iris at $18. and an adjustable iris at $58. +
I wear bifocals and want to sharpen front sight.

If you're serious about shooting iron sights, get separate glasses for shooting, and have a single vision lens optimized for the front sight in the dominant eye lens.

Knobloch and Champion aren't cheap, but they last for years if you don't abuse them. A new lens every year or so and you'll be set.

This is a nice cheap way to try an aperture system. It does help bring sights into focus. The set is plastic but decent quality and works.