Do you want the economical and greener lifestyles? Maybe you should start from minor matter to use the TrustFire protected 14500 rechargeable Lithium batteries. It features extensively long working life and high efficiency. The protected batteries are with integrated PCB Protection to protect the battery from overcharge、 over-discharging、 overload and short circuit for safe use.<br /><br />- Shell material: steel- Rated voltage: 3.7V- Internal resistance:                                                                                                                                 Dimensions: 0.51 in x 0.51 in x 1.97 in<br />Weight: 1.52 oz