If you're looking for a WLAN adaptor for use with aircrack, forget this. It's not tested and patched to work with aircrack and therefore it doesn't. But that's not the sole reason why I gave this product only two stars.
For the 2000mW power advertised, this adapter performs far far worse than its predecessor AWUS036H (which, by the way, is just a 802.11 b/g adapter - no 802.11n, with just 1000mW power). If you're looking for an adapter mainly to work with 802.11 b/g, then I'd strongly recommend you to get the Alfa AWUS036H (1000mW), which is far far better than this in terms of signal reception, even though it has lower power rating than this one. Moreover, even with a 9dB antenna plugged into this adapter, it performs far worse than Alfa AWUS036H.
However, if you're looking for an adapter to work with 802.11n, as the old Alfa AWUS036H that I recommended does not work with 802.11n, you have to get this one. I gave two stars because this product leaves you with lots of expectations and it fails to deliver even what its predecessor AWUS036H with lower power rating could deliver.