Single Dose Hopper Compatible for Mazzer, Niche Zero, FAEMA 900N, Mahlkonig EK43 & Fiorenzato Grinders - Blow Out Residual Coffee Grounds - Perfect Cleaning Tool for Home Baristas & Coffee Shops

I have a Niche Zero and it's a great little grinder. One of it's issues however is it's a bit like a little kid. It's messy. Though it has zero in the name if you jiggle it a bit... grounds will come out. If you tap you hand on top after grinding, grounds will come out. It's not Zero retention. So when this came available I was super excited. Now, finally, I can clear the grounds after grinding.I started as I always do by putting 20 grams of coffee in the Niche after RDT and turned it on. Like clockwork I had coffee. I took the Bellows and put it on top and pushed. Very little grounds came out. I jiggled the grinder side to side... more grounds fell than using the bellows.This is why. It's a bellows with a machined aluminum top cap. There are four holes in the top cap. I'm a fairly large man and even with these mitts my hand will not cover all four holes at once. Also the cap just rests on the bellows. So if you tap briskly the cap will likely fall off. Also, quite simply the bellows don't really fit the angled slope of the Niche. You have to try and keep the bellows centered and hold the lid and cover the four holes. Not ideal.Next, I tried it on my DF64 Gen 2 to see how it went there. Pretty much the same thing. The stock bellows on the DF64 were much better than this universal set for the same reasons above. The holes let to much air in when your trying to direct the air through the grinder. The lid has trouble staying on.For me, this is just average. I cannot recommend for the Niche and I'd probably order a new stock bellows for the DF64. I can't speak for other grinders so check out other reviews. I am giving three stars just because it does technically work. The machined aluminum lid has a nice feel. It seems well made... it just needs to be a bit refined before it can get four stars.