This particular icon has two upright rectangle shapes with two horizontal short black lines that looks like an equals sign. The two rectangle shapes has black lines in them, also.
This is a Equivalent 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 13,900 icons, all in the same style and quality.