This is the light head only for the Light and Motion Seca 1700 Bike Headlight. No battery pack, or battery mount is included.
If you already have a compatible battery pack, this is what you want.
Click here for a complete Light and Motion Seca 1700 Bike Headlight
Strap this light head to your forehead with the Light and Motion Multi-Sport Head Strap (Seca/Vega/Stella)