Custer Products LIMI HF18A-PHD AMBER LIGHT Battery Operated LEDs 18-diode LED safety flashers with 2 HD magnets attached to the back. This is our standard 18 diode LED flasher "beefed up" with heavy duty magnets. Approximately 6-1/4"wide x 4" high. These will flash up to 32 hours (or more) with 4 (AA) batteries. 18 super bright LEDs that can be seen up to a mile away, can be switched from "steady on" to "flashing" by pushing button on back.