Fortune PL-300BJ Battery Powered Ultra Bright LED Standard Police Beacon, 5" Diameter x 5" Height, Blue Beacon can be used as party decoration or in industrial setting to increase visibility, attract attention, or signal an alert 20 LEDs are arranged to simulate rotation of a police beacon; rotation speed can be adjusted to suit the application Magnets on bottom allow beacon to be attached to a vehicle or metal surface Runs continuously for up to 40 hours on four AA batteries (sold separately) Blue in color; measures 5" high and 5" in diameter