[18mm large eyepiece binoculars, larger images and clearer details] The image size of 12mm eyepiece (such as 10x25, 12x25, 10x21 binoculars) is 2.25 times, and that of 16mm eyepiece (such as ordinary 10x42, 12x42 binoculars) is 1.28 times. Large eyepiece binoculars make full use of 12 times magnification to provide larger images and ensure clearer details[16.5mm large BAK4 prism binoculars, super bright, clear field of vision] collect 32% more light than 12.5mm prisms (such as 10x25, 12x25, 10x21 binoculars), and 14.5mm prisms (such as ordinary 10x42, 12x42 binoculars) collect 13.7% more light 16.5mm Prism lens gives full play to the advantages of 42mm objective lens to collect more light and provide a brighter vision [The powerful 12x42 adult binoculars weigh only 1.25 pounds.] The 12x42 mm binoculars weigh only 560 grams, providing a 367 foot/1000 yard wide field of vision. The perfect binoculars are suitable for bird watching, hunting and sports events. Binocular binoculars with adjustable goggles are suitable for eyewear.