[Powerful Magnetic]: the stud detector does not require battery power, manufactured from magnets, which can generate 27 pounds of magnetic force, detect metal through 1/2 inch or 3/4 inch drywall or other thicker building materials; Work through ceramic tiling and up to 3/4 inch plywood paneling [Quick & Accurate Metal Stud Finder]: the magnetic stud ball can not only find and locate stud, but also can be applied to find any iron products, when your screws, sewing needles, keys, etc. fall into narrow gaps, use the product to pick up any iron material object [Compact and Portable]: Our stud finder is small and portable, the diameter of the studball is about 0.78 inch, about 2.59 inch in length, making it easy to carry with you wherever you go. It's the perfect tool for decorators, contractors, and anyone who needs to find hidden studs . [Works for most scenarios]:It can be found metal studs for the following construction materials:Carpet floor(3/4 inch), Plaster wall(3/4 inch), Concrete wall (5/8 inch), Ceramic tiling(3/4 inch), Plywood paneling(3/4 inch ), Wood frame walls(5/8 inch ) etc. Colour: Black Material: silicone + metal Package Contents: 3Pcs Stud Ball Magnetic Stud Finder 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 picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.