Features: brand new and high quality Premiun Quality: It is made of high quality ABS plastic, which is light-weight, fire-proof and stable. Free Combination: Battery holder has a card slot on the edge, you can freely combine the battery. Excellent Heat Dissipation Performance: There is enough space between the rack layers for ventilation and heat dissipation. Great Organizer of Battery: Must-have accessories for 21700 batteries. Note: Please note, installation requires top and bottom piece to work. Specifications: Material:ABS+PC Type: 1x2/1x3 Color:Black Hole Diameter: Approx.21.75 mm/0.85 inches Center Distance: Approx. 23 mm/0.9 inches Note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 10x Battery Holder Brackets