Snake River Prototyping 55mm URPro Cyan Filter for Tropical Blue Water Snake River Prototyping 55mm URPro Cyan Filter for Tropical Blue Water - Snake River Prototyping 1 Year Warranty Filter Type: Cyan Filter (CY) for Tropical Blue Water Filter Diameter: 2.16" / 55mm Ultra Low-Profile (No Outside Threading) Working Range: 12 to 60' (3.66 to 18.29m) Construction: URPro Optical Grade Polycarbonate