A couple weeks ago, I bought the 18 inch Hot Wheels bike for my older child (he helped pick it out). I put it together, and instantly, both he and my younger child loved the rev grip that was included in that bike. I went on Amazon then and there to look into buying one to put on the other bike that my younger child was inheriting (a nice 16 inch bike that only the older sibling had used for a couple years), and came across this one. I saw some negative reviews, but figured at 10 bucks it was worth the risk. After putting it on, I am happy overall with it, but it is not perfect - however, for a young child, all they seem to care about is that it makes sounds. Pros - I like the sound this makes. Other people don't and I can understand that. To me, the sound seems more like loud motorcycle, while the other one (the one from the Hot Wheels bike) sounds more like a race car. The sound on this one does not last long, and you have to crank it a bunch of times for sustained noise, but again I feel it just adds to the motorcycle styling, and I encourage that so my child cranks it all the time. I do like how it does not need batteries, as that means it will probably last longer, and I don't have to worry about the ooze from batteries. Cons - I think this one has a less appealing style than the one that came with the Hot Wheel bike, and is kind of plain. Not a big complaint, but I think they didn't put a lot of effort into the style. Secondly, and this is where I am actually disappointed, but for me is not a game breaker - is that the gauge function does not work. It will not go above the number 1. Now, I knew that this might be an issue going into buying it and thought it wouldn't really matter to my younger child, and I was right. I will say that I do not think this will be used in year to come, so I think this feature not working will never really be an issue. Now, if you are getting it for someone who is about 6 years old, they might notice, and wonder why it doesn't work, and then the novelty factor of this would disappear quickly. I think this is a nice toy to add to a bike. Both kids enjoy theirs, and if the gauge worked correctly then I would give it 5 stars. Even with the so so looks, and having to crank it a bunch for sustained noise (again, not a con for me), if you can get one with a good gauge (or if you are like me and think meh whatever) this seems like a good buy.