Optical power in Water: +13 dioptres
Aluminum body (6082) Hard anodized coated 40 microns
Two flat glass BK7 with anti scratch and anti-glare
4 elements, 3 groups
Compatible cameras: Optimized for sensor sizes 36 mm x 24 mm (135 mm full frame)
Magnification: x2.5 (Area Ratio x6.25) with 105mm F2.8 Macro Lens
Working Distance: 60mm - 85mm (from the front lens surface) 
Weight (air): 410g
Weight (water): 280g
Diameter: 71.7 mm
Length: 42.4mm
Depth rating: 60m