Vapcell Opus BT-C3100 V2.2 4-Slot Smart Charger https://www.everzon.com/vapcell-opus-bt-c3100-v2-2-4-slot-smart-charger.html The Vapcell Opus BT-C3100 V2.2 4-Slot Smart Charger integrates the minus delta voltage for NiCd or NiMh battery charging termination, and for Li-ion batteries charging to 4.2V with pre-selected constant current. (3.7 Li-FeO4 and 4.35 type high voltage batteries charging mode can be selected through switch on board) Easy to read LCD with back light Showing Battery Voltage, Charge/ Discharge Current, Charging Time and Battery Capacity etc. Parameters: Operating temperature: 0- 40℃ Current deviation: Max 5% Voltage deviation: Max 0.03V 4.2V Input Voltage: AC 100- 240V 50/60HZ Output Voltage: DC 12V, 3.0A Product size (Lx Wx H): 14.4x 9.8x 3.9cm Max charging capacity: Up to 20000mAh Power adapter: DC 12V, 3.0A (Output), 100- 240V, 50/ 60Hz (Input) Charging current range (mA): 200, 300, 500, 700, 1000, 1500, 2000 Discharge current range (mA): 200, 300, 500, 700, 1000 (li-ion cell battery only) Features: Voltage update rate is 30s instead of 60s. 35V charging algorithm is changed to 4.27V. 4.35V charging time can be very long because charging current is regulated in entering the CV stage at 4.12V, which is same as 4.2V type. New fan cover make better protection for cooling fan. LCD Screen Auto Circuit Detection Built-in Protected Circuit Over Voltage Protection Short-Circuit Protection Over-Charging Protection Over-Discharging Protection Packages: 1* Opus BT-C3100 V2.2 Charger 1* Power Adapter 1* User Manual