Optical power in Water: +23 dioptres Aluminum body (6082) Hard anodized coated 40 microns Two flat glass BK7 with anti scratch and anti-glare 5 elements, 3 groups Compatible cameras: Optimized for sensor sizes 36 mm x 24 mm (135 mm full frame) Magnification: x4.2 (Area Ratio x17.24) with 105mm F2.8 Macro Lens Working Distance: 27mm - 36mm (from the front lens surface)  Weight (air): 593g Weight (water): 379g Diameter: 71.8 mm Length: 60.3mm Depth rating: 60m