It's so small and compact - how can it possibly work? But it does! For anyone whose had to pop motorcycle brake pistons out with compressed air, you know how "interesting" that can be as they shoot across the garage. This little tool securely attaches to the interior of the piston and allows you to gently work the piston out.Note, it is small and after removing 8 pistons with it, my fingertips were sore. However, I don't know how else I could have gotten the pistons out without splitting the caliper.I used this on the OE gold Brembo 4-pad, 4-piston calipers on my Aprilia Mille. I did not split the caliper and was able to remove the pistons in order to clean everything thoroughly and to replace the rubber seals. This is another one of those specialty tools that can make every DIY bike mechanic's day.