I purchased this at auction.  It is a J.B. Owens Electric Lamp Base circa 1905.  Made in Zanesville, Ohio, prior to the Owens Pottery factory closing in 1909.  The "S" likely is an Owens company reference to the specific lamp company the pottery was sold to, and the "5" is an Owens mold number for the shape.  None of these lamp bases has the name "Owens" on them, but if its a "vase" without a hole in the bottom, it usually does have the Owens name stamped into the bottom.  The initials on the side are the artist for that lamp, Charles Fouts.  I have verified that this is the S5 shape.  There are 3 different numbering systems known covering 16 different lamp/vase shapes, *S0-S9, AS1 to AS15 and ALS13 to ALS16. This is marked S5. This is an exquisite   piece. No notable defects. It is antique. I carefully package for safe shipment and will add necessary insurance.  This is not an average piece of pottery! SKU #0071