Review on MinChen Rechargeable Waterproof Interface Headlamp by Darin Grosz

Replaced the old 4 cell 8.4v shrink wrapped battery for the Cree Xml T6 bike light. This works with 4 or 6 cell 18650. With 6 lithium batteries Cree lasted a maximum of 6 hours! This case also has a USB power connector. Batteries can only be charged with an 8.4V charger (NOT SUPPLIED), but if you are replacing an old, lightweight battery, this charger will work just fine. Also keep in mind that this case is larger than a sealed battery. It's 4.25 inches and the old battery is about 3 inches, so it's bigger and bulkier but with 50% more power.