5 LED Flashing LightOur highly visible and light weight abd water resistant safety flasher light with 5 super bright LEDs can be seen up to 2500 fee away (0.473 miles). You can select from 7 different light patterns-all LEDs on or all LED flashing-fast or all LED flashing slow or LED Flashing in a left to right pattern or LED flashing in a left to right pattern-fast or LED flashing left to right then right to left. This item has a built-in clip and includes a arm strap and bicycle attachment. This item is ideal for joggers and cyclist and skiers hikers or anything activity requiring visibility. The unit requires 2 AA batteries that are not included. The flasher measures 2 inches x 2 and three-quarter inches.