Description
DD05CVSA 2IN1 Charger + Boost Converter  is a module  that is designed to charge lithium ion battries with a charging voltage of 4.2V as stated in the specifications
This module has a maximum out put current of 1000mA and this helps to charge the battery fast and efficient
 
Specifications 
Type: 2-in-1 boost and charge modules
Charging voltage: DC 4.5V-8V (DC 5V recommended)
Charge current: 0-1A
Full charge voltage: 4.2V + -2%
Operating ambient temperature: -40 ° to + 85 °
Storage temperature: -65 ° to + 125 °