Amazon.com: 1Pcs 18650 3.7v 4400mAh 1S2P Li ion Rechargeable Battery Pack with 2.0Pin JST-PH Connector 16.28Wh/4.4A, Blue, 6.6 x 1.8 cm (19.28Wh/4.4A) : Health & Household
Amazon.co.jp: Household Battery Rechargeable Battery 2S2P 4.4AH 18650 Li-ion Battery 7.4V 4400 MAH Battery, Blue : Electronics
Factory Supply Rechargeable Cylindrical 18650 Batteries for Medical Equipment UFX 18650-2S2P 4400mAh 7.4V Li-Ion Battery