The Sigma front light does not keep what they promise, I tried different batteries, Sigma battery, 3900mAh and 2300mAh battery and loaded with the Sigma charger or an external charger the batteries, the lamp lasts a maximum of 35 minutes, so not suitable for me, because I have 35 minutes to work fahre.Meine old Sigma Ellissoid Front Light, has with normal 2300mAh battery over a week gehalten.Die lamp is not recommended.