These propellers are pretty delicate but fly really well. You don't need to get too much spin to get them to launch, so even small kids can manage. They are extremely difficult to put together, though. The straw part is very flimsy and bends too easily. They fit so snugly in the hole that several of the straws had to be trimmed because they got bent while trying to put them in. I also ended up using scissors to scrape out the holes a little to make the straw go in easier. If giving to small kids, make sure you assemble beforehand! It's not a two second job like you'd imagine.