ROI from ancient greek flow. Roi door is designed as an elegant and silent sliding surface. The minimal design of the rail system and its silent movement make this doors collection unique in its essentiality. The stainless steel railing system make it possible to hang the door to masonry, but also to create walk-in closets. ROI can be used for houses, offices and public spaces. Roi door is designed as an elegant and silent sliding surface. Sliding door with pulley sliding system.