7-21x21 8-30x21 10-40x21

Key Features ：
● BK7 Reverse-Porro Prisms
● Compact Reverse Porro Prism Design
● Fully Multi-Coated Optics
● Exceptionally Wide Zoom Range
● Fold-Down Rubber Eyecups
● Center Focus Knob
Overview ：
10-40x21  Zoom Binoculars from  deliver versatility and portability that easily fits in a pack, pocket, or purse. The wide 3x magnification range is well suited for medium- to long-range viewing and ideal for sightseeing and glassing on the trail or in the woods.   proprietary zoom lever, lLocated laterally to the right eyepiece, is ergonomically placed to be accessible with either hand for easier use.   Fold-Down eyecups help to ensure a comfortable viewing distance for almost any viewer—even if they wear eyeglasses.
Optical Performance:
● Wide 10-40x zoom range
● 21 mm objective lenses
● Compact reverse-Porro prism design
● Multi-Coated  optics ensure images are bright and clear with improved contrast and accurate color representation

● Wide 30°- 48°  apparent angle of view
● 159 (10x) to 63 (40x) foot field of view at 1000 yards
Use and Handling ：
● Large center focusing wheel is easy to manipulate, even when wearing gloves
● Right-eye dioptric correction enables users to compensate for individual optical prescription

● Fold-Down  rubber eyecups for comfortable use with or without eyewear
● Close 5' short-focus distance
● 2.1 - 0.5 mm exit pupil
● 11.0 - 8 mm eye relief
Construction Details 
● Lightweight plastic chassis
● Protective black rubber armor provides a slip-resistant grip
● Textured palm pads improve grip security
● Weight: 205 g
Performance ：