A retrofit system includes a body, a cup and a valve. The body has a top wall and a plurality of side walls defining a opening and a chamber and is configured to be connected to a gas meter such that the chamber is in fluid communication with a chamber of the gas meter. An inlet channel is configured to be in fluid communication with an inlet of a diaphragm disposed within the gas meter and an outlet channel configured to be in fluid communication with an outlet of the diaphragm. The cup is disposed within an aperture located in the top wall and defines compartment configured to receive a radio frequency (RF) controller and a power supply. The valve is connected to one of the inlet or outlet channels and is electrically coupled to the RF controller and the power supply. The valve is configured to close in response to receiving an electrical signal from the RF controller.