All we can say is "wow!" We had thought that our 1.3-pound tamper, The Silver Surfer was heavy. This heavyweight, a true champ, called "Ali," tips the scale at 28 ounces! The conical handle of this coffee tamper is beautifully angled, and the tamper's mirrored surface reflects whatever it's on. This coffee tamper is a work of art, and a hefty tool - meant for MEN, and women who are very strong. Highly recommended. This tamper works fine in a 58 mm portafilter. (Note that 0.5 mm. = 1/50 of an inch!)
Most standard espresso machines (semiautomatic and automatic) use 57 mm or 58 mm coffee tampers. Many people want coffee tampers that fit snugly into the portafilter, and some prefer a millimeter (or so) of wiggle room, so that they can more easily manipulate their coffee tamper while tamping. But note that a coffee tamper doesn't get pushed down into the bottom of the filter basket (which can be slightly tapered) when you're tamping. So it's the inner diameter at the top of the basket that you'll need to measure to size your coffee tampers correctly.
You should read our article on "How to Use a Coffee Tamper Correctly for Uniform Extractions" if you're not exactly sure how to use coffee tampers. Note that "How to Use a Coffee Tamper Correctly for Uniform Extractions" was written with the professional barista in mind, so there are various moves described that sound complicated, but have more to do with not touching the coffee directly with your hands than with pure function. Using coffee tampers correctly is not complicated. The Silver Surfer coffee tamper gives you lots of weigh, and a solid piece to work with. It's a great coffee tamper.
We recommend that you do not wash coffee tampers in the dishwasher, because over time, the dishwasher will damage their beautiful glossy finish. To clean these coffee tampers, simply wipe them down with a damp cloth. You wouldn't want to damage the gloss on these coffee tampers. Your coffee tamper should not be "dirty" in the first place. These coffee tampers makes great gifts.