This is a Timezone +7 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 12,700 icons, all in the same style and quality.
There is a horizontal rectangle with zigzag lines on the top and bottom. Inside the rectangle are four columns of small parsed dots. The bottom right corner of the rectangle is overlapped by a circle about a quarter of the size with the plus symbol then the number seven inside of it.