Two-Stage Propane System
From Free Knowledge Base- The DUCK Project: information for everyone
First stage regulator: adjust for any differences in tank pressure, installed at or on the tank, decreases the pressure between that tank and its service line to 10 PSIG .
Second stage regulator: located at the house, decreases the propane pressure to the lines inside the home at safe and appropriate levels for appliances, usually an equivalent pressure of about 11" W.C.
The brand RegO aka Rego LPG tank valves and regulators are very common in the Midwestern United States. An example is the Rego LV3403TR First Stage High Pressure Regulator .
