This is the only Double Bubble float I've found on a Korean float.  The Inner Ball measures approximately 3/4 of an inch across.  There is an opening in the seal to the inner ball.

This 3 1/2 inch float was formed in a 3-piece hand carved wooden mold and has a dappled appearance.  It has a light net pattern frosting covering about a quarter of the float.

This float was beachcombed in Alaska on a remote black sand beach of the Bering Sea.