This float is stamped with a newly verified maker's mark.  By 'newly verified', I mean that two floats with the same mark have been found.  I've got one and I've been told that the author of 'Glass Ball Marks' has the other.

The mark itself is comprised of two distinct parts inside of two semi-circles that don't quite meet to form a whole circle.  One of the inside parts looks like a single wiper on a windshield.  Below that are a couple of long wavy lines.

These floats were found in Japan in 2009 by our old friend at Seashore Collections.

This float has excellent provenance having come from the ex-Deborah Hillman collection.