UMLIFE 4pcs 18650 Charging Board Dual USB 5V 2.4A Mobile Power Bank Module 186 50 Lithium Battery Charger Board with Overcharge Overdischarge Short Circuit Protection DIY USB Power Bank Board - Newegg.com
Quick Charge Version 10*18650 Power Bank Case Dual USB Mobile Phone Charge QC 3.0 PD DIY Shell 18650 Battery
Amazon.com: Speedy 18650 Battery Charger XTAR PB2C USB Output Function, Portable Li-ion 18650 Battery Charger Box w/USB Port and LED Display for all 18650 Batteries(Batteries NOT included) : Electronics
MakerFocus 4pcs 18650 Charging Board Dual USB 5V 2.4A with Overcharge
Hacking a USB Battery into a 18650 Charger - YouTube