All Li-Ion Battery packs must connect to a protection circuit module to protect Li-Ion Battery from overcharge, over discharge  and to prevent accidental battery explosion due to its extra high energy density. The protection circuit is specially designed for 3.7V Li-Ion Battery. Please refer to the specification on how to wire the pcb to battery.  

Please be advised that this circuit will provide the following protections:

Prevents 3.7V  Li-Ion Battery pack from overcharging 4.30 +/- 0.05V

Prevents 3.7V  Li-Ion Battery pack from over discharging 2.40 +/- 0.1 V

Maintains 3.7V Li-Ion Battery pack's discharge current lower than 6.0A.

Protect battery from short circuit and wrong polarity

Dimension:34mm(1.33") x 5mm(0.19") x 2.0mm(0.07") 

Max Weight: 0.1 Oz (3.0 grams)