This has a 13mm adjustable eyepiece for greater ease of use by eyeglass wearers and brighter viewability This high powered monoscope has a BAK4 Prism for the clearest images. Includes fully multicoated green anti-reflection glass lenses for 99.8% light transmittance allowing the best and brightest possible for image Whether you are outdoors enthusiast or a photographer, or just going on a you will not only have immediate magnified viewing, but can also take photos on your smartphone Preminum extra-wide Smartphone Adaptor fits almost any phone It attaches securely to the monocular and will not fall off, weigh down or distort the monocular for image like other phone attachments do and has special padding so it will not damage your phone or phone for case Super telephoto ZOOM 300-40 Monocular is the for ideal monocular for you and your family to get from 10x-30x adjustable magnification and exquisite views of wildlife, landscapes, action or just about anything...anywhere