Description: Features: 100% brand new and high quality. This battery box holder fits for 3pcs or 4pcs flat 18650 batteries(Optional) Parallel connection, safe and easy to use. Output voltage DC 3.7V. Simple DIY recharge power supply. You could use this case with your own battery to form power supply system. Kindly remind: 18650 batteries are not included in the package, you need to purchase separately. Can only use the 18650 battery of which positive pole is flat top. Specifications: Item Type: 4x 18650 Parallel Battery Holder Box Material: Plastic + Metal Color: Black 3 slots Size: 7.862cm 4 slots Size: 7.87.82cm Cable length: 10cm/3.94in (Approx.) Design: Parallel Connection Type: 3 slots,4 slots(Optional) Fit for: 3x or 4x 18650 3.7V battery (Not Included) Output: DC 3.7V Red positive, black negative. Quantity: 1 PC (other accessories demo in the picture is not included) Note: 1.Transition: 1cm=10mm=0.39inch 2.Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. 3.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! 4.No retail package Package includes: 1 X Battery Box Holder (Batteries are not included.)