Like Tony mention, good question. There's so many choice and so many sizes. I mostly need something that crashes well. So durability is #1, especially where I fly Lol. I have Fossil 180 and 210. They say that there indestructible and so far I'm a believer. A little pricey but you get what you pay for. Here's the site and take a look Quadcopter Frames, Equipment and Accessories | Fossils Stuff