This is a multicache. It is not at the posted coordinates.
At the posted coordinates, you will find a TOTT that's necessary for the final.
Input the engraved markings from the TOTT into the solution checker to get the final coordinates.
At the final, use the TOTT to access the cache, then return the TOTT to its original location.
The cache has room for trackables and swag (each in their own large Ziploc, to keep them from getting lost).
Congratulations and FTF honors go to Beauzarian, Larry the Pool Guy, and ganseyiii!
You can access the final coordinates with certitude.