I have used these sprinklers for over 20 years and they are hands down the best!!! We have very hard water and it just takes it and keeps going.  My last one is still working but it is very old so I thought it was time to purchase a new one.  You won't be disappointed with this sprinkler, especially if you have a lot of yard to water.  I set it and leave and come home and it is off.  I love it!!!