The solar panel comes with TY10S provides power supply to the light, which makes TY10S a self-contained and care-free light unit. Also, with the solar function, the light is easy to deploy to almost any condition and any emergency case. Robust body built and surface coating provides good protection against hash environments. TY10S is equipped with an 8Ah NiMH rechargeable battery which could power the light up to 20 days when the weather is cloudy & rainy. NiMH battery is also a clean power source with no pollution. The NiMH battery is also easy to find almost anywhere. TY10S is also available with an optional on/off switch for storing and protect battery from over-discharging.