J.C. Flenniken was an important citizen of the city of Strawberry Point, Iowa. He was president of the Strawberry Point Bank and so esteemed he was appointed as an external auditor of the Iowa Department of Agriculture. A noted Republican state senator, Flenniken was also (briefly) a fishing tackle manufacturer, as evidenced by this May 1907 advertisement in Field & Stream.
The float itself was patented by David R. Lewis of Manchester, Iowa on September 15, 1903 (Patent #738,923). This cork bobber had a unique internal mechanism, and carried the patent date stamped into the side.
It's a neat bobber and a very rare one.
-- Dr. Todd