You've just bought a new car, or rebuilt the motor on your classic, and you know there's going to be metal particles floating about in your oil's recirculation system. Here's an easy way to contain those particles within your oil filter. Just place this powerful magnet next to the filter and it snaps firmly into place. Immediately, you'll start accumulating engine particles as small as 2 microns in size on the inside of the filter wall. It's that simple, and may be used time and time again. Just remove it from your old oil filter and place it on your new one! Cut your filter up next time and you'll be shocked at the amount this Filter Magnet holds! Cheap insurance if you plan to keep your baby for a while. Made in the USA. HD models provide extra protection for diesel and racing engines. To order, measure the outside diameter of your oil filter, then select your style and size below.