Not free, but this is what I gleaned from the MTH order site; when I typed in the product number that was on my order receipt, (FB-0000014), it led me to a 6-pin wireless drawbar, (see below), then to the drawbar collar #FB-0000015. The collar seems to work well, at least for now. Clem K's use of plastic tubing sounds good too. Thanks to all for the great comments.
Wireless Drawbar Cover
$2.00
(plastic) (for 6-pin wireless drawbar) (42.0mm long) (is placed directly on the wireless drawbar) (for FB-0000014) product # FB-0000015
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