I have replace several of my 30+ year old rain-bird sprinklers with the Krain sprinklers over the years. I've not had a failure as of yet. These are very robust and well built sprinklers. They are very easy to set the pattern you want. Once you do one it will take less than a minute to do the others. There are instruction on the sprinkler and a good video on YouTube on how to set the pattern. However, there are no instructions in case you happen to set the left start in the wrong place but I figured out that if you unscrew the entire cylinder cap lift up, and then rotate the entire assembly to the correct start position, drop it back down, and then tighten you'll be good to go. The right position you set by turning the arrow with the provided key to the spot you want it to go to. This comes in handy should you ever move a sprinkler or purchase one where someone has already turned the cylinder and accidentally set the left start.