The binocular for 25x and 40x is a precision optical instrument with variable magnification, which is used for long distance observation under various climatic conditions. The binocular can also be used to measure roughly the distance and the height of target and the angle included between two targets. When it is used to observe various targets, the binocular provides a distinct image, comfortable viewing, real and stereo perception. The diopter and interpupillary distance of the binocular are adjustable, thus it can fit the observers with different diopters and interpupillary distances. Therefore, the binocular is of great assistant in the activities of amusement, hunting, shipping, fishery, forest fire prevention and long distance observation for various scientific research purposes.