This stud ball has 27 pounds of magnetic force and does not require batteries. And this magnetic stud finder can find 40 or more steel studs on a drywall with the thickness of 5/8inch in less than a . Detects quickly and accurately screws or nails in wood walls or behind drywall. Metal can be detected through 5/8-inch drywall, wood or 3/4-inch plywood, ceramic tile, etc. The stud ball can detect metal and does not require any marking or reading . The magnetic stud ball can be directly positioned and fixed in the exact location so that construction can be carried out directly. Unlike other types of stud finder, this stud ball can detect metal not only through 5/8-inch drywall, wood framing or other thicker materials, also through 3/4-inch ceramic tile and plywood. Widely Applicable: As this stud detector has enough magnetic force, it can be used as a hook to hang up some metal tools. It can also be used to find some metal objects dropped on the ground, or even used to pull up metal objects dropped into the crevices. (Just tie a long enough rope in the rubber ring of the stud ball) color:Red Material:plastic Package Contents: 2 x drywall magnet Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.