A small blue float made of concentric circles of gas-filled tubes. Up to 8 cm in diameter (usually 4 to 6), with a clear chitinous semicircular sail above and small tentacles below. The sail is angled left or right from the long axis of the float. Floats far offshore, but may be blown onshore in large numbers by some winds, especially in spring and early summer. Found worldwide in the temperate and tropical oceanic zone.