Contents:
Plastic Tank - 4¾" (12cm) x 6½" (16.5cm) x 5" (13cm) deep with an aluminium lid, bracket & cropped bolt & nut for mounting in a greenhouse. 

An internal Torbeck Valve - to control the water supply, to maintain a fixed head of water (just like in a toilet cistern).

Inlet connectors - ½" Elbow & Hose Connector (accepting standard ½" hosepipe) - to form the inlet for mains water connection.

Outlet connector - Tank to ¼" Connector - to create an outlet to take ¼" tubing. 

Sometimes mains pressure can be a bit erratic.
 If a tap is turned on somewhere else in the property the pressure and flow can suddenly drop as the supply is diverted to this second outlet.
 When this outlet is then switched off a sudden surge can be generated causing a weak or insecure joint to blow.
 This device allows safe and consistent running of a mains supplied irrigation system by automatically switching off the supply if the set pressure is exceeded. 

 Some pumps have a factory setting which can be too excessive for a particular system. The regulator can be set to maintain a lower pressure, suitable for the system.