ThruNite T20S CW Max Output Of 255 Lumen Battery Cree XP-G2 LED with a lifespan of 20+ years of run time/Uses 1CR123 /1RCR123/ 116340 battery Max output: 255 lumens with XP-G2. Out put mode: Firefly:0.04Lm 100hours,Low:11Lm 19hours, High:255Lm 55min