The BWJ2325 6x21mm compact waterproof binocular used BAK4 prisms and roof system. The combination of the two gives you clear images that are bright enough.? With extra wide field of view・ close focus・ phase correction coated prism and the BAK4 optical lens to take your bird watching experience to a new level of clarity and brightness.Rugged rubberized body that is shock resistant and extra durable. The rubber body offers a comfortable non slip grip.A pocket size design that can be folded for easy portability. And in lightweight・ at just about 300 gram.With nitrogen purged to be waterproof and fogproof in order to withstand tough weather conditions and rugged environments.With twist up and down eyepieces and large focusing wheel are super easy to use.It suitable for hunting・ bird watching・ camping・ hiking・ backpacking・ traveling・ concerts・ sporting and any other outdoor adventures.