Anyone who uses this tool will agree that the underside of the magnet (where the nail head meets the frame) gets a lot of stress and mine snapped in two on the second use. Luckily . The tool itself is steel and after I glued the parts back into its cage it stays fine, but all of this could have been avoided with a harder steel magnet part. There is no exact guide as to how much force or depth the nail should go into the frame of the picture. But eventually I got used to it after 2-3 shots. After 20+ photo frame cleanings, it definitely saves me time, gives me confidence and relieves me from worrying that I might break fragile glass fronted frames or damage very thin profiled wooden frames or backs from before, thanks to this tool I could reuse the original nails and this allows me to access picture frames to check the quality or authenticity of the art, and often to troubleshoot fox or mold issues, or to remove simple build-ups of static dust myself. And after that, you won't need a dust cover again because you can easily access your content again. I recommend this tool to any household that has old picture frames with sharpened nails. And the price on amazon.com is the cheapest.