Does anyone know what the difference is between two different couplers I have found for Instep trailers? They are both listed as #SA074, but one is steel and the other appears to be black plastic. The steel one is shown on the Instep site, instep.net, and other sites. The black is also shown on several sites, Ebay included. It is also somewhat cheaper.
If anyone has any experience with the black one, is it strong enough to do the job? Any help appreciated.