58mm. is the most common, but plenty machines use different sizes. What machine do you have? 58.4mm is often described as a competition tamper, and offers a snugger fit in a 58mm basket.
3D-printed Ti please. Thin wall, polished, some kind of clever, mathematically optimised lattice core. I don't mind if the tamper section is 3D carbon instead of Ti. List:
58mm. is the most common, but plenty machines use different sizes. What machine do you have? 58.4mm is often described as a competition tamper, and offers a snugger fit in a 58mm basket.