Saim Plastic 3.7V 18650 Batteries 4 Pin Battery Holder Case Black Pack of 5 This battery box holder with pin connector, fit for 2 x 3.7V 18650 batteries. With weld leg design, you can easily to put the battery in it. Battery Type: 2x 18650 3.7v(Battery is not included here.); Parallel Series Connection. Each item body size measures about: 7.8 x 4 x 2.6cm / 3.1" x 1.6" x 1"(L*W*H) Note: Please do not separate, maintain, or refit the product.The wires are thin, and the structure of this product is only fit for very small current load, DO NOT connect it to a load that will cause large current, stop using this product if the wires are hot.