Johnny, this mag pouch will fit up to 2.48 inch belt, with slight mods to the cross straps within the main belt loop. I have this pouch and can tell you it is very versatile beyond typical belt applications. It holds the clip well and can be attached horizontally to other gear for easy access in tactical situations.

Depending on belt width, you will most likely have to remove one or more of the small 'cross braces' in the belt loops to make the size correspond more exactly with your belt width. I would imagine there will be instructions for adjusting the loop size with the pouch.

Johnny, not as is. You would need to remove a segment off of the bottom belt loop support posts so the Duty Belt could be threaded through.

Will fit belt sizes from 1.25 to 2.48. so it should work with a duty belt. However, there are much better choices such as Safariland or Bladetech.