The Hydro Shark is a heavy-duty moisture sensor that detects moisture in carpet, drywall, and wood. The flashing bio-hazard light and audio alarm let you know when moisture is found. This state-of-the-art tool is made from stainless steel with a non-slip rubber grip. While other tools are prone to dents and damage when bouncing around the back of your van, the Hydr Shark will stand up to daily wear and tear and keep working job after job. 9V battery included.