ITEM NAME:2pcs Circuit Boost Board 134N3P Charge Discharge Module DIY USB Power Bank4.2 ME Features: Material: ABS Input voltage: 3.7v to 5.5v Charging current: 1A (max.) Output current: 1A (max.) Output voltage: 5V Battery charge cut-off voltage: 4.2v ±1% Battery discharge cut-off voltage: 2.9v ±1% Discharge efficiency: 85% (input 3.7V output 5V / 1A) Charging: The red light will flash Fully charged: Steady red light Standby current: 8uA Product Size: 2.3*1.8*1cm Packing list: 2pcs X boost module.2pcs X boost module. Charging: The red light will flash. Charging current: 1A (max.).