Using a special firmware image provided by Nordic Semiconductors and the open source network analysis tool Wireshark, the Bluefruit LE Sniffer can be used as a low cost Bluetooth Low Energy sniffer.
NOTE: This product can only be used to sniff Bluetooth Low Energy devices. It will not work with classic Bluetooth devices or transactions.
Since nRF-Sniffer is a passive solution that is simply scanning packets over the air, there is the possibility of missing packets using this tool (or any other passive sniffing solution). In order to capture as many packets as possible, be sure to run the sniffer on a USB bus that isn't busy and avoid running it in a virtual machine since this can introduce significant latency over USB.