2.BAK4 prism and multi-coated lens for improved light transmission and image clarity. Feature: 1.Life waterproof,which can better extend the service life of the telescope.Easy to deal with any harsh environment. 4.Broadband green film coating to increase light transmittance and make the imaging color fuller. 3.Central focusing knob for smooth operation. 5. and compact, good for camping, hiking, concerts, bird watching, hunting, traveling, golfing, sporting events and other outdoor activities.