Flush head sprinklers are quite common in systems from 20 or more years ago. These systems are still very serviceable, and the flush head spray brass replacement nozzle is an excellent way to maintain them. Each pack contains 2 precision-machined brass nozzles with excellent uniformity. The male thread pattern on the nozzle matches up with the female thread pattern on the flush head body. A flush head wrench or our 16-in-1 tool (sold separately) make it simple to remove the existing plastic or brass nozzle and replace it with the new brass nozzle. Recommended operating pressure is 30 PSI. For outdoor irrigation use with cold water only.