KNS Precision Enhanced Push Button Pivot Pin .250 Diameter

This is a must for polymer lowers, plus you don't lose 7,814,356 detent and springs as well as breaking 2 fingernails and making your fingers sore trying to install it like mil spec takedown pins, only downsides are it's a bit expensive and it isn't retained so be sure not to lose it, fit is great and very secure, a bit more difficult to use than mil spec pins (after install of course) but not hard by any means.

I really hope the one I bought was a lemon because the idea of these pins are amazing. But the ball bearings on mine would not retract in when i pressed the top pin. I thought they would work after being used a little bit and maybe things would be good after some pressure. When I put the pin in, it came out the other end with the bottom plate missing. So now it doesn't function well and the insides are exposed to the elements which would only cause more problems (if it were to work properly in the first place). at this point, i think i would rather struggle with springs and detents than a piece of garbage now.