Power bank case suitable for Max 5 piece lithium ion battery of 18650 model no.
You can select battery also if want. Circuit has 3 USB port and one charging port of Type B.
You can use 5, 3000 mah battery to make 15000 mah power bank or 5 pcs 3000 mah battery to make 15000 mah battery. Circuit has indication of 4 led. 1 USB port is 2.1A and other is 1A,1A rated.