Raster is a small tool for designers and developers that sits in your menu bar. It lets you display two grids and two guide lines to float above your Finder and application windows. While Raster is being displayed, everything on your screen is still clickable, so you can seamlessly continue working with your applications. When running multiple displays you can select on which screen Raster is shown. If you're using Spaces you can choose to move Raster to the current Space you are working on. Raster supports both Retina and standard displays and requires OS X 10.7 or later.