GTIWUNG 18650 Battery Case Holder with Lead Wire Bundle, 8 Pcs 1/2/3/4 x 3.7V Series DIY Battery Storage Boxes, 1/2/3/4 Slots Black Plastic Batteries Case with Pin + 5Pcs Cable Straps: Amazon.co.uk:
Adeept 2Pcs 2 Slots 18650 Battery Holder Case with Wire and 2.54mm JST Connector, Batteries Connected in Series 7.4V, Solderless 3.7V Battery Storage Box Holder for DIY Projects: Amazon.co.uk: Electronics & Photo