"- Total outer diameter: 21.5 cm- Easy "click-in" construction- Cast and polished 316 stainless steel accessories- Strong ABS molded design, anti-aging, anti-corrosion, ultraviolet resistant.Specification:- Round shape porthole for boat/yacht/RV/industry cars- Corrosion-free synthetic fittings and waterproof, durable rubber seals- Tempered glass for strength, clarity and chemical resistance- Both fittings can be loosened to allow you to open the porthole- Easy to install, pre-drilled countersunk mounting holes (screws not included)Package included:Porthole 1 pieceNote:1.The real color of the item may be slightly different from the pictures shown on websitecaused by many factors such as brightness of your monitor and light brightness.2.Please allow slight deviation for the measurement data.3. please allow 1cm-2cm error due to hand measure."