It’s good and it works but it could be great with a couple of changes.
The first would be to make a snug fit instead of a looser one size fits all. The funnel sits inside so when removed there is a small gap around the edges where the ring was. I feel a singer fit and the ring would sit on top removing that coffee gap.
The second less important but more of a QOL improvement would be the use of magnets to hold it on the portafilter.
Don’t get me wrong it’s still a good product with a quality build but their choice to make 1 dosing ring fit both 49mm and the new 51mm portafilters was a mistake. I would rather see to different products that have a perfect fit.