Specification: Material: ABS plastic+Poly-carbonate Size: 100*80mm Pore size:18.4 mm Combination:4x5 Cell Quantity:20/30/40/50 pcs Feature: Suitable for DIY combination of import batteries With professional battery holder to replace the traditional general adhesive, which would brings convenient combination and more firm connection, as well as brings convenient maintenance of the battery.its the best choice of the battery combination Type 18650 belong to necessary support of high-end battery combination, can withstand high drop, high strength support, easy to heat dissipation, convenient combination, fixed specifications, and free combination With card slot at edge, any size can joining together, match up firm, with strong, and no need for other device connected by vibration test. Package List: 10/20/30/40/50 x Lithium batteries Plastic holders