Double Bubble inside a 6 inch float.  The inner ball is approximately 1 1/2 inches across.

This float also has many other interesting characteristics that set it apart.

First, it has a great net that has complete integrity and still has some tar soaked into it.

There's also quite a bit of tar stuck to the side of the glass.

The glass has an inclusion (possibly a small kiln stone) and thousands of tiny bubbles.

Finally, you can see the remnants of both barnacles and coral.

All in all this makes for a wonderful display float.

Found in Northern Japan.

This float has excellent provenance having come from the ex-Ramon Fulton collection.