Funny thing the first time I installed one in an older transmission when I removed it it did look like a porcupine I was shocked and thought my tranny was f’d. So I got a white paper towel to wipe it off with so I could start picking the pieces out to see what they where and they magically all disappeared into the paper towel like a slime. Here it wasn't big pieces just trillions of microscopic sub micron grit that where in suspension in the magnets magnetic field. Cleaned the plugs ( one in the drain one in the full catching oil as it’s coming off the gears) and next oil change they only had 1/4 of the debris of the first time, they cleaned up any and all ferrous grit that even oil changes don’t take with them. I have them in every vehicle I own (including my quads and lawn mowers even) in every plug that sees oil, trannys, transfer cases, auto transmissions, everything. Next time I find one that looks like a porcupine I’ll take a picture of it, simply amazing.