It gives surprisingly even coverage because of the sprinkler's design. The inner construction creates a vortex, forcing the water to exit in fine droplets, very evenly dispersed over the entire area of the circle.
The most amazing part of all this is that a similar design was originally marketed in 1899 but was out of production for most of the century following.
3-1/2" overall. Made of non-rusting zinc/aluminum. Great for watering small lawns or gardens, or for focusing the water on one particular spot.