This valve is characteristic of being pre-adjustable, it can be adjusted at the pressure value before installed in system(better read 
pressure via pressure gauge as optional)

Technical specification
Material
Body:CuZn40Pb2 or material required
Cover:PA66
Seals:NBR

Check valve:----
Pressure gauge:2-4bar

Performance:

Medium:water
Max working pressure:16bar
Preset pressure:1.5bar
Max working temperature:65℃
Connection: inlet 1/2'' ISO228-1 with compression end
                  Outlet 1/2'' ISO228-1,female