If you're really interested, email the site on that paddle strop/stone combination. The owner's a member & may have some thought's on what it actually is, though on his site he say's it's similar to an arkansas.
Why risk buying any unknown strop or stone from a vendor, or the bay? The risk is they may well end up being a POS. You can get something tried & tested & inexpensive from Kenrup or TM.