I was looking for a way to attach a 4 prong rotary dial telephone to our current modular jack, and discovered a source for this great item!
Makes it extremely easy to connect to today's phone jack without kludgy wire stipping, etc. Just plug the phone into the 4 prong jack, and plug the modular cord into your telephone wall jack.
Shipping anyw in the US is $2.50.
Thanks for looking!