This version of mark WP #19 Ki 木 is quite interesting.  The stamp has been pressed deeply into the seal of this 7 inch float.

Typically, mark WP #19 is found on 3 inch floats.  This 7 inch float with WP #19 may be a rare find.

The symbol in the WP #19 mark is Ki 木 which translates to 'tree'.

It's quite heavy for its size and is slightly out of round.  This indicates to me that it may be an older float; possibly pre-WWII.

There are extensive remnants of shell life on this float, too.

I bought this float on eBay in 2020 and it came with quite a colorful story:

"This float was one of many found on Micronesian atolls and islands from 1963 to 1983.  In particular, this fishing float was beachcombed on the island of Saipan, Mariana Islands in the 1970's.

My parents were fanatical float "finders" not collectors.  They traveled on rusty scows like the MV Rananim, MV Palau Islander, MV Yap Islander, and Hafa Adai throughout Micronesia and found what the sea chose to give up.  Thousands of early morning trips to windward side beaches where the majority of the floats were broken on the reef or beach.

Every authentically beachcombed float tells a story."