I remember back a few years, we got an email from a so-called “Tool Expert” from one of the big box stores asking what SDS Plus and SDS Max were. He sold the tools, but didn’t understand the bits. If he really didn’t understand those concepts, I hope he could sell people one of these as well. It’s an adapter between the two different shank styles.
If you’ve got an SDS Max tool and want to use an SDS Plus bits, then this is exactly what you need. I also noticed the note that this would also allow an SDS Max tool to use a standard drill chuck adaptor, which would be a nice addition to those tools as well.
Looks like The Max (SDS Max, that is) just got an upgrade in utility.