I like this bell, has a great sound and on my black bars of my Trek Madone blends in with the rest of the components so I don;t look like a noob. I ride a lot in a local state park that has a lot of foot traffic and this does a good job of gently but clearly announcing my approach.
One small flaw is that on more bumpy pavement, you can hear a subtle quiet ringing (not nearly as loud as an intentional stroke of the hammer) but not unnoticeable.
As bike bells go, there seems to be a few that are small and decently looking, and most that would look wonderful on a bright pink tricycle, not my road bike. As for the stealth look for a bike bell, this has it all. You put this your handle bars and no one is going to notice it at all, you could paint it pink and no one would know it's a bell, they may wonder what the pink stripe is on your handle bars is though.
As for sound loudness, there is a compromise, the bigger flashier bells are louder, but people hear this bell with I'm coming towards them so it works. In the past I've had a larger bell and I noticed that when I used it while in a small group as we pass pedestrians, that everyone could hear the bell, but couldn't tell where is was coming from. With this bell you can do the same and be in total stealth mode.
There are many places that require a bell be on a bike and this makes for a nice alternative to every other bell that I've seen. I wish it was a bit loader, but people hear it, so it works.
On a side note: the lever that is pulled back to strike the bell, this is the bells weak point and you want to be careful where this is located. If it can be rubbed against while your bike is in storage, or transportation, there could be some damage to the lever. My hand slipped one day while riding and knocked it out of alignment and had to be snapped back into place to ring, I'm wondering if I could have knocked it off completely.
All bikes need a bell, there just comes a time when you need to nicely and politely let somebody know you are behind them. Out on the trails this can be a hiker, runner, another bicyclist, or even somebody on a horse. The Oi Bell does all that with an adjustable sound that does the equivalent to "pardon moi" to "Oi! get out of the way!" depending on how hard you pull back on it's lever.
I went a long time without a bell, decades really, because I could not stand the looks of the cheap chrome things most bike shops push on their customers. Bulky, ugly, easy to destroy in a fall, they quickly become pitted and rusty in a single season of riding. The Oi Bell is none of that. You will barely know it is there, clipped around your bars, until you need it. I find myself ringing it sometimes just for the sake of hearing it.
Sunday riders who feel they need the sonic power of a church bell may not like this little baby. I do. I commute via bike 14+ miles 5 days a week. NYC law requires a bell, so I wanted something light and sleek. I hardly ever touched the last bell I had. I find my voice to be far more effective. The only time I use this polite solo xylophone is when I'm overtaking another cyclist and we're both riding slowly. When I'm going 25-30 mph by the Navy yard I'll give an unaware pedestrian a "yo" at 30 yards. No bell is as good as the voice when you're really moving. Even at 15-20 mph pedestrians who love to stand or suddenly step in front of one in the bike lane seem to respond better to a voice. This little bell is a sweet piece of design though. I approve. As for those who say it chimes inadvertently, I find it only tinkles a bit over railroad tracks, grated drawbridges, and the occasional pothole or steel road plate.
Looks great, very nicely packaged, and easy to install; however, the large size was slightly too big on my 25.4mm handle bar. With the provided spacer the bell was still too loose after trying to pinch it together completely (stickers specifically warn not to over-tighten with hex bolt). I tried using the 3M rubber tape included for the 23.8mm as instructed, but that made it too wide to fit the bolt in. I emailed KNOG if there was a way to fit this on properly, but there was a "Please allow us 7 business days to reply" response.
Was about to return the product, but decided to wrap a few rotations of plastic medical tape on the handlebar, install the spacer over it, then tighten the bell, which worked perfectly. As others have complained about the rusting of the springs, I simply sprayed them with a rust protector before attaching. The bell has a very pleasant single tone, definitely not an alarm, but it serves my purpose. If you have a favorite high-end bike, I highly recommend this product for the perfect design and classiness that it brings.