These are replacement nozzles for 15mm Naan Impact plastic sprinklers.
High quality plastic construction
Colour coded to match existing systems
As water travels through the nozzle, it can slowly wear out the nozzle over time, creating a change in the rate of your water application. A yearly check on your nozzles is recommended depending on your slit content; this will maintain the nozzles emitting the correct rate of water as well as to check for general wear and tear.