Here ya go. By the way, they are called a dog coupler.
Petsmart:
http://www.petsmart.com/global/searc...ch_results.jsp
Petedge:
http://www.petedge.com/shopping/brow...eyword=coupler
I have one from Petsmart. It was kind of hard to find it on the shelf. It was not in any packaging, just hanging behind some long leashes. Hope this helps!
Missy