The best thing about the Hasbro Nerf Whistler Darts are clearly the toy it is designed to be used in conjunction with - namely, the Nerf Gun. These little darts are accurate and extremely lightweight as they are primarily made of foam. The tips are made of rubber (or bendy plastic - I'm not sure which, in spite of the fact that I have totally dismantled one) and as such, can cause a little bit of a sting especially at close range. Clearly it's the lightweight foam that enables them to travel the distance that they do but it's also the foam that deteriorates somewhat quickly. They get trodden on, they get bent and ultimately they need to be replaced. Thankfully, they are not expensive and most supermarkets stock the replacement ammunition. All things considered these darts are pretty robust and by the time they need to be replaced, your kids have experienced many hours of good fun. I deem it money well spent.