Use the UpShot espresso shot mirror with a bottomless portafilter to gain insights into your extraction, check for channeling, and whether your grind size is right.
The UpShot mirror is unique as it sits on the edge of the cup, bringing that mirror closer to your portafilter and giving you a better close-up look at the extraction. The UpShot mirror is made from ultra-thin tempered and edgeless glass and ships with an adhesive magnetic dot so that it can easily be magnetized to your espresso machine or near your coffee station.