Use Propane Safely, Use GasStop! The ACME GasStop is an emergency shut-off safety device for propane gas systems. In the event of a major leak, ACME GasStop will automatically shut-off 100% of the gas supply instantly and automatically shut off the flow of gas. A 'must have' safety device to protect families with RVs that have propane systems on board. Manufactured to the highest quality standards, individually tested, and backed by a 5-year warranty. Easy to install, with a high-quality propane pressure indicator for the ACME valves. QUESTIONS? PLEASE VISIT OUR FAQ PAGE