The 'B' flag, or Bravo flag, is used to represent the alphabetic character 'B' for use in a message between boats. It also means "I am taking in, discharging, or carrying dangerous cargo."
From the International Code of Signals, this long-lasting nautical flag is made from nylon fabric with double-stitched seams, canvas heading with rope and toggle. Made to order. Allow 2 weeks for delivery.