Sketch 3 is a perfect tool for iOS, Android and Web design. It is a vector design tool entirely focused on user interface design. It’s easy to pick up and simple to use for anyone with little to no training. Just like native OS X apps, you have a familiar user interface with a Toolbar, Navigator and Inspector It’s perfect for designing multiple devices, and it is very easy delivering assets. Sketch uses a single unit, styles only relevant to UI design. It comes with a built-in iPhone previewing tool called Mirror. With Sketch´s Artboards, you can design multiple screens in a very efficient way. It comes preloaded with a number of user interface templates for iOS 9, Material Design and Responsive Web. Sketch 3 can be downloaded via the homepage and costs 99 $ ( 109,42€). The only disadvantage is, it´s only Mac compatible.