$1.95
The Netafim SpinNet (check valve only) with the pruple pin opens at 28 PSI and closes at 13 PSI.
When irrigating upside-down in greenhouses, net-houses or tunnels, using a SpinNet and VibroNet bridgeless micro-sprinklers give you uniform water distribution and the check valve stops the draining and dripping from the overhead supply line. The result is perfectly uniform crop yields and no damage to the plants directly below the heads from dripping water.