This is the one I use, I pinched it from the wifes knitting machine when she wasn`t looking lol
A simple split pin or cotter on the spindle trips the count.
plenty of them on ebay http://cgi.ebay.co.uk/Row-counter-for-Knitmaster-Knitting-machine_W0QQitemZ250092962013QQihZ015QQcat egoryZ28146QQrdZ1QQssPageNameZWD1VQQcmdZViewItem
Regards Russell