It's a winter Sock that covers the Ridgerunner. One of the minor complaints about it was that the suspension had to be taken apart to install and uninstall it. Using the Dutch biner in place of the apex triangle thingie (small triangle in fishbite's photo) eases the process. Normally the two dog bones (Amsteel cords running up from the corners of the bridge) are larksheaded onto that little triangle, and near to be untied to install and uninstall the spindrift Sock.
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