This is a Sign Out Filled 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 12,800 icons, all in the same style and quality.
This icon is a very line line drawn in a circle with a small portion left blank on the right hand side. Inside of this empty portion is an arrow that is pointing towards the right. It starts in the center of the circle and ends right at its edge.