Belkin Pocket Power 10,000 mAh
If you like to buy accessories and products from brands you know and trust, consider the Belkin Pocket Power 10k charger. Belkin has been around for years, and everyone knows who they are at this point. Or you should.
The Belkin Pocket Power delivers 10,000 mAh of battery, so you can recharge that 3,000 mAh battery in your Galaxy S9 or iPhone nearly three times. That's enough to last an entire weekend without being near a wall outlet.
You get two full-size USB ports for all of your devices, and a microUSB to recharge the battery itself. As a bonus, they offer three colors to match your iPhone.
or from Amazon for $32