Colorful & Light tamper with flat ripple base from MHW-3BOMBER. Available on 51mm and 58,35mm. 

The ripple base tamper is a newer type of coffee tamper with a cool design – it has circles or ridges on the bottom. These ripples make sure the water flows evenly through the coffee during extraction, giving you a tasty and balanced espresso shot.

What's neat about ripple tampers is that they give you a feel for what you're doing. The ridges on the bottom create a textured surface, so when you press down on the coffee, you can sense it. This helps you tamp the coffee consistently each time. Calibrated tampers offer a similar kind of feedback, just so you know.

51mm is the usual size for the home espresso machines from brands like DeLonghi and most of the Chinese/Turkish brands. 58,35mm is the competition size tamper and fits all modern professional espresso machines with 58mm portafilter and also the home machines like Gaggia Classic Pro & Rancilio Silvia.