In summary: Do not buy it...
I got the first one when I built up my gravelbike about a year ago. After 1000 km chain and cassette were worn so bad I had to replace both...
I then got 2 new cassettes (the same ZTTO ones) for both my wheel sets, thinking it was my fault for not checking the chain sooner... I also started with 3 new chains that I wax and rotate every couple 100 km. I only used one cassette that I switched between wheelsets.
So after about 2000km the cassette is not worn yet, but is starting to make a lot of noise. Really loud creaking. Took me a lot of time before I found out it was the cassette. After reading the reviews on Ali I do not seem to be the only one... (but most of the reviews are very positive because when the cassette starts creaking you can't leave a review anymore). The problem are the rivets that hold the cassette together come loose and there is play in the cassette and this starts to make a lot of noise.
I had the other new ZTTO cassette laying around so I put that one on with a new chain, hoping I would be released from the noise for at least some time... But the first ride this cassette also started to make a really loud noise every pedal stroke. It really drove me crazy. I have since ordered a SRAM 10-42 cassette, but in the meantime I applied a lot of oil to the cassette and the previous 2 rides it has been silent. But it will only be a matter of time...
When this cassette starts to make noise I will bin all the ZTTO cassettes, mount the SRAM cassette and never look back...
Financial analysis: 3 ZTTO cassettes at 45€ each vs SRAM cassette at 85€ is not really a lot of savings...