I've used one it's good so far, here's the original write up.
http://www.retrobike.co.uk/forum/viewtopic.php?f=1&t=235105
http://www.retrobike.co.uk/forum/viewtopic.php?f=1&t=235105
Wytze":28xrjxif said:the BBB version is M8, BUT not sure about other extenders, AND not sure if the BBB ones are different from other years.