Knight's armament micro 300 meter folding rear sight - Knight's Armament Folding Micro Rear Sight 300 Meter

This is a pretty basic lollipop style BUIS. The lollipop does not wiggle side to side when deployed. It does not lock in the deployed position (other than a nice detent). You lift it to the deployed position. No spring activation with a button or lever. Comes with a small peep insert that can be removed and possibly lost (knew that before I ordered it). KAC makes a similar 300M rear sight with a standard A2 windage knob and it is much more expensive. Not sure why that is.