Motorad ST-16 Safety Lever Radiator Cap

I've always bought similar ones that are like this because I believe in safety and sometimes when you have to check your water level or on older model cars you need to vent and the water scalding hot will go all over the place burn you get all over the engine burn your legs whatever but this little valve releases all the pressure and you could easily check your coolant levels and add water or coolant as necessary on the safest radiator cap