I found your original post, same subject, but the old links went nowhere. So I hopped on the "Google-ator" and took a long ride. After quite a few detours, I finally ended up at RVCAMS. Either a different company or they moved to Louisiana. Also found PROVIX (in the UK), who had a lot of Weldex products. May be more, but I quit.
Anyways, $16 each at RVCams, and $10 each at Provix. May be time to research a new camera system, never did get decent operation with the Weldex.
BTW, it never fails to amaze me how a simple google search for an innocent something can end up including links to 'girls-gone-wild' type sites.