The OnTour Map Measurer from Kasper & Richter is used to determine distances on maps and blueprints. Roll the wheel over the route you're measuring, then convert the measured distance using the map's scale. This map wheel employs the most common inch-to-foot plan scales – 1/2", 1/4", 1/8" to 1' – and is equipped with inch and foot rulers. The OnTour features a rotating counter and a quick reset to zero, and is protected by a durable metal housing.