Four red LEDs. Three modes: alternating flashing, flashing and steady-on. Alternating flashing: lumens – up to 10, runtime: up to 65h. Flashing: lumens – up to 10, runtime – up to 65h. Steady-on: lumens – up to 10, runtime – up to 50h. Impact resistant – up to 1.5m. Water resistant – up to IPX4. Uses two CR2032 batteries (included). Perfect for biking, jogging, walking or any outdoor activity where you need to be seen in.