Yesterday, I received @Pahawi 's Speedie Caseback Opener and I am very impressed with it. Solid brass, 6 exact points of contact, 6 oz. in weight. It even has a through hole to insert a screwdriver should you need extra torque. Best of all, it not only fits Speedie Moonwatches but lines up with Seamasters as well. SM 300, 2913, 165.024 and even the smaller SM 120, 165.027 all open safely, scratch free, with this tool. Highly recommended! Much better and safer than the cheap, adjustable variety.