This shape is basically a rectangle with rounded edges. On the right center of the shape, is what looks like the right side of a regular rectangle protruding outwards. On the inside are two vertical lines on the left.
This is a Low Battery icon. We've made it in iOS style
, first introduced in iOS version 7 and supported in all later releases up until now (at least iOS 11). This style is based on thin two-pixel lines and is optimized for 50x50 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 13,700 icons, all in the same style and quality.