Lezyne LIR 2 Cell Battery Mega Drive $39.95
Keep it lit
If you put in most of your training hours in during the wee hours of the morning, chances are you own Lezyne's Mega Drive light. Make sure it never goes dark and have a replacement battery on hand at all times.
This is a LIR 2 Cell Battery for the Mega Drive light. It is sold as a single battery.