Clever design and works well. Very reasonably priced for such a light weight component.

These do not last long before you start experiencing chain skip. Within 2 months of use, I started to get significant wear. I got a replacement and 2-3 months later, it happened again. I contacted the company the second time to see if I could get a refund and never heard back. It shifted well but on high power outputs, I could not keep my chain from hopping all over the place. I keep my chains in great shape and use a chain gauge to make sure it is not getting too much stretch. So it wasn’t a worn chain issues that made this thing wear quickly. These probably aren’t the best cassettes to buy if you ride a lot and ride hard.

I was bummed it did not work with the freehub on Easton Road Wheels. Its not always compatible with Shimano or SRAM, But Light and awesome looking.

Used this with a SRAM AXS Red 11speed 1x set up. A little loud but crisp shifting and spacing is accurate. This is my second one (had a 11/32 before in rainbow) probably got about 4-5k miles out of it the year prior and then the 22t started to slip. For the value you can’t beat these. Highly reco

Really easy to fit on shimano HG cassette wheels. Seems nearly identical in use with GRX Di2 and Ultegra bikes I have. Durability? I’ll have to put more miles on it.

This is the third one that I’ve purchased, I use one on my trainer and one on the road. The machining is something to see. Holds up fairly well, I replaced my road cassette after changing my chain and finding a couple of my favorite gears slipping. But close to 2k miles on the cassette and I just didn’t change out my chain often enough.

After installing the 11-28 on my tri bike it slipped in the middle 3 gears but you need to fine tune your shifter. I'm using a Campagnolo med cage so a bit of fiddling at first. Now have no issues with slipping and put of 5000 miles on it up step hills as well and 3 Ironman Races so far. I just brought a 2nd one for my road bike. I'm going to the lightest cassette on the market apart from the Taitamunm ones that run $400 plus so these ones for $60 is a way better option.

Pleasantly surprised. I'm picky and this thing is lighter than Shimano/Sram and works fine. I'm using Ultegra Di2 and have this cassette on multiple bikes.

Updated (second update), after some mileage and buying a third one (jump down).I was in the market for a new 11-34 cassette and due to supply chain issues, my options were rather limited. The JFOYH ("Just FOllow Your Heart") ultralight cassette seemed like an interesting option over the Shimano CS-HG800-11 (Ultegra) cassette in the same size. One difference, the jumps in the cassette are not the same as the Shimano cassette (11-13-15-17-19-21-23-25-27-30-34T for Shimano vs 11-13-15-17-19-21-23-25-28-31-34T).The larger difference is that exactly half of the JFOYH cassette is aluminum while most cassettes in this size are all steel. This will certainly have some ramifications regarding durability. That said, after a few rides it seems to shift smoothly when paired with an RD-RX800-GS (Ultegra Rear Derailleur with clutch) and a YBN chain.All that aluminum results in the cassette coming in at 229 grams which is lighter than the 11-28 Ultegra cassette it is replacing at 244 grams. Ostensibly, the comparable Shimano cassette weighs 335 grams which is a significant weight difference.The aluminum gears are all one piece, while the rest of the cassette (save for the 11 tooth) are connected to a central spindle. Sort of akin to an Eagle cassette only with more aluminum gears (granted XD and XDR cassettes are completely attached).And now I have put over 1k miles on the cassette and have some further thoughts.First off, it has worked flawlessly, in terms of shifting, et cetera. At this point, I've had it on for over 1k miles (I ride about 230 miles a week on it) about half of which was on gravel and 100 miles of that was for the Trinidad Rad Dirt gravel race in Trinidad, Colorado. Most of the exposure/dirt has come from "moondust" like fine dust that you find in the Front Range of the Rockies. However, that race was extremely muddy for the first third. So muddy that the YBN SLA chain I put on at the same time as the cassette, showed about 0.6% stretch (using a Park Tool CC-2) afterwards.Which is all to say: it's been through the wringer a bit.It shows no signs of wearing (shark-toothing, chipping). 1k miles isn't a lifetime, but I'm rather bullish on that aspect. I'm also rather particular about having a clean drive train. You can see some wax on the cassette in the updated photos. I'm a Molten Speed Wax user (in lieu of regular lube, you completely degrease your chain, I use an ultrasonic cleaner, and melt the wax, let the chain sit in it, etc... it's the cleanest and most efficient lube, but that's another story) and only resort to using Banana Slip (a tungsten based wax) in extremely muddy conditions (and it doesn't interfere with the Molten). If you're less particular about your drivetrain, you might see more wear on the aluminum cogs.It also looks rather stunning, with the open back of the aluminum.This is where the praise ends.If you buy this cassette you will absolutely need to buy a Shimano lockring (more on that in a moment). The included lockring isn't big enough for either my Park Tool FR-5.2 Shimano Cassette Tool or Wolf Tooth pack wrench with steel HG insert. I thought maybe if I tapped it in a little with a soft faced mallet, it would open up, but that did nothing but damage the soft aluminum of the lockring.As soon as you get it, toss it in the recycling bin (I think they can recycle anodized aluminum).I then made the mistake of buying a third party lockring, which while it fit the tool, didn't have properly chased threads... (another review). I ended up just repurposing the Ultegra lockring off my older cassette. Works fine, no issues. To avoid my mistake, you can buy a Shimano HG lockring (doesn't really matter if it's Ultegra, Dura-Ace, whatnot).The shipping times can be a bit slow, but if you're looking for a lightweight cassette that appears to be made well, it's worth the investment other than the terrible lockring.Further update: I've put even more miles on it, still working fairly well. I ordered a second one for use on my smart trainer... the lockring on the second one fits a tool, but seems to either be threaded wrong or has too much anodization on it as it feels like it will strip the freehub assembly as I try to thread it on.Still pretty happy with it, just be sure to keep the chain clean and fresh.And the latest: in the supply chain constrained world of 2022, I was trying to build up another bike with eTap AXS and, of course, the 10-36 cassette (in any variety) from SRAM was unavailable, unless you're willing to pay double MSRP on eBay (of course).To that end, since i still had the OG HG (Hyperglide) freehub body (in addition to an XDR for the upgrade), I ordered one of these in 12-speed, 11-34 as a make shift solution.Because this data is so hard to find online, I can say this: the JFOYH 12-speed 11-34 HG works fine with eTap AXS and the flat-top chain. I never had an issue. And the 12-speed cassette came with a lockring that worked flawlessly (so they must have improved the process there).I will say that while it works, the JFOYH cassette, with it's simpler design (no shift ramps, etc) is not as smooth as the Rival 10-36 I found a few weeks later (after much scrounging), but it will absolutely work.