This is a Plus 1 Hour 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.
This icon consists of an outlined circle representing a wristwatch with a small rectangle placed on the right side representing the crown. Two parallel lines run vertically behind the circle, representing a wrist.