Amazon.com: Fielect 10Pcs 3x4 Cell Spacer 18650 Lithium Battery Holder Bracket for DIY Battery Pack, 18.4mm Hole Dia : Tools & Home Improvement
4*10 18650 Battery Holder ( Integrated, Not Stitching) Used For 4p10s 36v 10ah Li-ion Battery Pack Electric Bike Battery Bracket - Tool Parts - AliExpress