I can only recommend. Have as a predator protection device already in use for years and had since then no unwanted visitors more in the engine compartment. Latest equipment held for about 3 years. Installation is simple, even if the description sounds very complicated. Making only connection to the battery and attach unit in the engine compartment, it already sends very high tones. Sounds are audible from children, "older" people (from 20) but heard no longer perceive this frequency.