Beileshi 30X40 Brass Scalable to Stretch Zoom Monocular Maritime Nautical Pirate Telescope Ship Spyglass Scope The Material of the Whole body is Metal.30X magnification, auto focusing porro prism,Field:52-1000MCoating:Blue Membrane,Aperture:40mm BK7 optical glass roof prism,Classic appearance ,total alloy material, overall plating copper and AR coating rugged and durable Focus Methods:adjust the objective lens and same time slightly adjust the eyepiece lens The stretch length scope: 5.3inch-13.1inch,Zoom Mode:tract zoom,you can put it in your pocket and bring it anywhere Accessories:Specification/rope/vocal concert/lens cloths/ leather bag