CO2 Flow Gauge (Regulator) attaches to your CO2 tank and regulates the flow of CO2 gas to the euthanasia chamber to bring about a humane, efficient, and safe dispatch of wildlife according to AVMA standards.
The euthanasia chamber should not be pre-charged, meaning you don't fill the chamber with CO2 and then place the animal into the chamber. The trap & animal should be placed in the chamber and the CO2 gas turned on slowly to prevent stress and panic.