Just dont mow over the top if its a bit high- I have replaced 3 because of this. Also be careful when installing 1/2" threaded fitting as easy to break off plastic fitting in base if handled roughly. Good idea to Tee a short spur off the underground pipeline using flexible hose and put an elbow on to screw into this, as it is then easier to adjust the height in situ which is very difficult if the unit is just screwed onto a Tee in the pipe under the lawn.