Brass Pop-up head sprinklers are quite common in systems from 20 or more years ago. These systems are still very serviceable, and the pop-up head is an excellent way to keep them in good shape. The version with pop-up action gives an extra inch or so of spray height which makes it more suitable for grass, while a traditional flush head is more common in above-ground applications such as shrubs and flowerbeds. The brass nozzle includes an adjustment screw which allow you to reduce the spray pattern down to 75% of its maximum radius of 15 ft. Pop-up heads have 1/2-in. female pipe threads (FPT) and you will typically mount them on a 1/2-in. male pipe thread (MPT) rigid PVC or cut-off riser. The Pop-up head wrench is an accessory that makes it simple to remove and install heads without extensive digging. The Pop-up head nozzle is easy to replace with a brass head spray nozzle with male threads.