Airpcap Usb Adapter Do We Need Airpcap Adapter To Crack Into WEP Network?

Do we need Airpcap adapter to crack into WEP network? - airpcap usb adapter

Hello friends, I put the paper on the shortcomings of WEP WPA.
Can someone tell me why we AirPcap USB adapter to crack your WEP? If so, why do we need USB AirPcap actually do for us to crack WEP.

What is the market price for AirPcap USB adapter?
Please try to answer and explain if you can.

Thank