It's a good little red dot for the price. The overall sight is about an inch wide and 4~ inches long. It's almost full metal and a little on the heavy side. Has 3 brightness settings and you can choose from green or red. Red dot is also adjustable. I use it on my G36K and although it's wickedly accurate I'd recommend using it on small submachine guns and the like. Still works well on my G36K. IT ALSO HAS PARALLAX COMPENSATION! No more centering the red dot exactly in the middle; even if you aim through different angles and viewpoints, the red dot aims exactly where you're pointing the gun, not where you're looking! This is very surprising considering that it's a $19 red dot.
Nearly all metal construction
Heavy (as in not-toy-like)
3 Brightness settings, green or red dot of your choice
Long lasting battery
Cheap for the value
A little heavy (as in makes your rifle a bit more noticeably heavy, but not too bad)
Rating: [5 of 5 Stars!]