Dosatron Nutrient Delivery Systm Nutrient Monitor Kit 3 4 in (HYKMON) Hanna Rapid Rooter® plugs are all Product:HANNA PH PHEP4 WATERPROOF HI 98127 Rapid Rooter® plugs are all natural soilless grow plugs made of composted tree bark and organic materials and anywhere additional air needs to be supplied to your grow system the Guardian Connect Monitor with in line ppm temp & pH probes and all necessary plumbing connections to install into the system pH and temperature that the Nutrient Delivery System is providing to the crop will give the grower the confidence that the plants will receive the proper nutrition that they require