D-Tools SIX has been re-designed to increase productivity and efficiency by making it easier to get to core functionality for estimation, design and delivering projects faster than before. SIX is designed to be your platform for growth and has been completely re-designed to make it faster and easier than ever to perform the key business functions- estimation, system design, and project management. A database-driven process ties these elements together to reduce time, help eliminate errors, and increase ROI.