This is a Timezone -8 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 12,500 icons, all in the same style and quality.
A horizontal rectangle with zig-zag lines at the top and bottom and four columns of parsed dots on the inside. There is a circle overlapping the bottom right quarter of the rectangle with a plus symbol followed by the number eight inside of it.