5600mAh External Mobile Power Bank Charger ?
8200mAh's is the difference 
Most phones have around a 2000mAh battery. The 5600 will charge your phone from completely dead to fully charged almost 3 times. The 13,800 one will charge it almost 7 times. Most tablets are between 5,000-10,000 mAh's. If your charging a tablet you may want to go with the larger battery.
I personally carry a 3000, and a 5,000 and use them to charge several tablets and phones for my family when we are out and about for the day. If you're out camping or away from a power source for multiple days you probably will want the larger one.
Most phones have around a 2000mAh battery. The 5600 will charge your phone from completely dead to fully charged almost 3 times. The 13,800 one will charge it almost 7 times. Most tablets are between 5,000-10,000 mAh's. If your charging a tablet you may want to go with the larger battery.
I personally carry a 3000, and a 5,000 and use them to charge several tablets and phones for my family when we are out and about for the day. If you're out camping or away from a power source for multiple days you probably will want the larger one.