Modular type - To unlock the handle , pull it until the orange marked underneath it shows. And then push the regulating handle again to lock after setting pressure.
T type - To unlock, unscrew the nut attached to the regulating handle. To lock the handle, screw the nut after setting pressure.
When regulating pressure, turning the handle to the right raises the pressure of secondary side. Turning to the opposite(left) direction drops the pressure.
Regulating pressure range of the secondary side is less than 85% of the first side.