Wow, a lot of Chinglish in that listing. It looks like it's a similar mechanism to the Element fire extinguisher except with a thermal trigger and different form factor.
Early intervention is key to reducing damage so that could be helpful, but with its suggested location at the front of the hood, it might not trigger very early if the car is in motion. I had that type of engine fire while driving my first wife's car, a Ford Escort on the highway. Heat from the exhaust manifold had risen through an open warm air intake and melted some of the plastic air filter housing which dripped onto the exhaust manifold and caught fire. Airflow from the front pushed the flames backward burning the ignition wires. The resultant misfire was why I pulled off the road and opened the hood. Then the flames had a chance to spring up and grow larger. I was able to beat the flames out with a T-shirt.
Would this extinguisher be triggered by this event? Maybe. Had it been a gas fire things would have progressed much more quickly and this device could have made the difference between a repairable car and a write-off. But I'd want to see some reviews of this before trusting it to work when needed.
elementfire.com
