The polypropylene surface grants the best projection quality as well as writing, erasing and rewriting with erasable markers. Screen-App is also suitable for writing with permanent markers which can be easily removed with a specific detergent or mere alcohol. It will always look new afterwards! The sandwich structure of the screen includes an inner foam layer which absorbs the imperfections of the underlying surface, namely a plastered wall, still keeping the smoothness and the comfort of the front surface unaltered. Such three characteristics mean an advantage for the installer whose installation is simplified. In a couple of minutes the screen is positioned, taken off and repositioned several times with no damage and no effort; advantages for the screen owner, corporation or school which will benefit from the screen strength and long lasting characteristics. Little maintenance will enable the use of the screen over the years without any problems and even after months of intensive use it will be perfectly removable and usable elsewhere; advantages for the final user, teacher or speaker who will appreciate its optical characteristics during projection and the optimal writing quality without worrying about the marker to use. Ideal for classrooms and conference rooms, it is easy and quick to install. Moreover ScreenApp is writtable with interactive pens, dry and permanent markers, it is washable and can easily be removed and reused.