The light absorption sheet absorbs the light at a well-lit area and emits the light at a dark area for several minutes. A measurement of the normal grade can be made with 45 degrees vial. A measurement of a pipe can be made with U-grooved measuring face. [History of Levels] A Level, which becomes widespread worldwide today, originally came from Europe. People established a standard of a level through they dug groove and pool water in it in ancient time. A level has high valuation, which were made up and improved, in long history by an old craftsman finding that water was flat. "A stage of creative activity of strengthening the ties between person and person, and people and things by bringing together the latest technology and sensibility." In 1970, EBISU Co., Ltd. has been established as Manufacture and Distribution of Levels. Head Office : located in Tsubame city in Niigata prefecture, Japan. [Quality assurance & Environmental conservation activities] The ISO9000 series - The quality of our factory’s manufacturing system has been recognized. We are the first level gauge manufacturer in Japan to be given the ISO (International Organization for Standardization) 9001 for quality assurance. [Products list] 1. Digital level 2.The level corresponds with Building Regulations of Japan 3. Levels for plumbing 4. Angle Measuring Levels 5. Each kind of level 6. Clear Levels 7. G-LEVEL for Constructions 8. G-LEVEL for Civil Engineering 9. Basic Level 10. Parts 11. Vial 12. Presbyopia mirror, Loupe. EBISU and EBISU DIAMOND are registered trademarks in Japan.