Cool then look here
http://www.nsr250.net/forums/viewtopic.php?t=2793&highlight=clip
and then here
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1,1&item=4598291371&sspagename=STRK%3AMEWN%3AIT
$99 and they where ace, you can adjust the pole to suit! Im sure if you look up the seller he'll have some more, and yes they fit a 21
Cheers