This is a Restart 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 13,000 icons, all in the same style and quality.
Idea of Restart Icon by Krys
We've received the idea on March 01, 2012 and created the icons on April 11, 2012
Metro style icons for shutdown, restart, sleep, hibernate to pin to windows 8.
Simple not too over the top, based on the existing windows 8 shotdown icon