I looked and most of the adapters I could find were made to adapt "other brand" accessories to the tool, so it seem like the adapter I am thinking about should be a Dremel made adapter but all I could find made by Dremel are adapters to adapt Dremel blades to them not the other way around.
Looking at Rockwell's web site didn't see one either.
The only one I could find is a Bosch adapter model OIS001, which states
"The Bosch Oscillating Multi-Tool Adapter allows you to mix and match different brands' oscillating tools and accessories. This adapter gives you the freedom to buy different products from different brands and be confident that they will work together. Accessories represent the secret weapon in getting the most from an oscillating tool. Bosch offers the widest variety of accessories, from specialty blades to cutting saws, using the best materials and design methods. And thanks to the OIS? adapter, Bosch accessories can be used on a variety of oscillating tools from other manufacturers"
Is this my best bet or is there an adapter I am missing?