These work well.  I installed them where I needed an extra inch of height from leveling out some land in my yard.  i previously had some 4 inch Rainbird's that were probably around 3 years old.  I installed these fairly fast, and the spray is strong and covers the grass well.  I only took one star off because you can't get the spray down to 8 feet.  It's about 10 feet at the lowest setting.