Hi Unreg,
The K9 anti-twist locks are the plastic washers with a tang on the underside and 4 "canine teeth spikes on the upper side that lock into the footstrap inserts on the board and the spikes stick up and engage the nylon webbing in the footstrap.
They keep the footstrap from twisting.
The are shown on the RH bottom of this link page:
http://www.star-board.com/SpringSumm...gn_details.php
Hope this helps,
Roger