Amarine-made Boat Yacht Rectangle Opening Portlight Porthole 15-3/4" x 7-7/8" Replacement Window Port Hole - ABS Tempered Glass, Color: White, Black 4mm thickness tempered glass. ABS Anti-aging, Anti-ultraviolet. Casted and polished 316 stainless steel accessories. Easy "click-in" construction. Corrosion free synthetic fittings and durable rubber seals.