Seatbiscuits are designed for the rugged outdoors. Constructed from the
finest marine grade vinyl (18 assorted colors) and is sewn with Gortex
thread and seam sealed for a completely encapsulated beanbag. Seatbiscuit is
filled with Virgin polystyrene encapsulated beads, which are designed for
the harsh marine environment.The size of the bag is measured as
circumference.

http://www.seatbiscuit.com