Amazon.com: Adeept 2PCS 2Slots Battery Holder with Wire and 2.54mm JST Connector and Plug for 18650 Battery 4 Cell Case, Batteries Connected in Series 7.4V, Solderless Battery Storage Box Holder for DIY
Amazon.com: Plastic 18650 Battery Storage Case 2 Slots x 3.7V for 2x18650 Batteries Holder Box Container with ON/Off Switch, Set of 5, by Ltvystore : Electronics