Well built; but you have to figure out the per click moa and bdc drum values for your gun. - UTG Pro AR15 Super Slim Fixed Rear Sight, Picatinny

I bought 6 of these. All required the elevation index to be reset (1.5mm hex key required). 3 would barely bottom out at 6/3 but not fully. 3 bottomed out 1 click away from reaching 6/3. In my case, I adjusted the index to allow me to go 6 clicks below 6/3 for a 200 yard small peep site index.

The BDC yardages on the elevation drum won't match your rifle; so you will have make notes or put your own marks on the drum to match your rifles trajectory and moa click values.

There are 69 clicks of elevation. One complete turn of the knob is 24 clicks.
There are 81 clicks of windage. One complete turn of the knob is 10 clicks.

My setup:
16"BBL Midlength A2 Front Sight/gas block
Sight mounted flush with rear of upper receiver.
Sight Radius = 17.25" (peep sight to front sight post)

My MOA calculations for my setup and other setups:

Elevation
~0.50 MOA per click with a 12.4" sight radius
~0.43 MOA per click with a 14.5" sight radius
~0.41 MOA per click with a 15.25" sight radius (Carbine A2 Front Sight)
~0.36 MOA per click with a 17.25" sight radius (Midlength A2 Front Sight)

Windage
~0.76 MOA per click with a 12.4" sight radius
~0.65 MOA per click with a 14.5" sight radius
~0.62 MOA per click with a 15.25" sight radius (Carbine A2 Front Sight)
~0.55 MOA per click with a 17.25" sight radius (Midlength A2 Front Sight)

Spreadsheet formula:
Elev Click MOA = (DEGREES(ATAN(0.0018044618/Sight_Radius)))*60
Wind Click MOA = (DEGREES(ATAN(0.0027559055/Sight_Radius)))*60