Your iPhone 12 already comes with a big enough battery to last you up to 20 hours (depending on the model). The iWALK 4500mAh Ultra-Compact Power Bank gives your phone’s battery a boost. It is the size of a lipstick and can charge an iPhone 11 a full charge. It works with thicker phone cases too.
The iWALK power bank comes with a built-in Lightning plug. It has pass-through function, so you can charge your phone while recharging the power bank. It measures 3.0*1.8*1.0 in. You can find out more about it here.