The name itself suggests the purpose of pocket binoculars which is to be able to store and carry them around in your pockets. They are small, lightweight and very easy to hold in hands and carry around the neck. They’re perfect for birdwatching, traveling, safari or any outdoor observations (sports events or concerts). To ensure smaller dimensions and compactness they usually have roof prism system that offers better optical technology and binoculars are therefore brighter. Other occurring prism system is reverse Porro. Due to their smaller size the lens diameters in pocket binoculars are between 20 and 26 mm and the magnification is normally between 8x and 12x. With most pocket binoculars the bridge folds at two different places to bring both optical barrels together – that way they’re really compact, suitable to store in pockets and offer closer interpupillary distance. However, in some rare cases the bridge folds in only one place which makes them less compact. Because they are intended to be used outside they are usually waterproof and fog-proof to prevent any inside fogging when exposing your binoculars to extreme temperature fluctuations. To keep their compactness, they have short eye relief which makes them less suitable for eyeglass wearers.
In comparison with compact binoculars, pocket binoculars have smaller magnifications and smaller objective lenses. But in comparison with opera glasses, pocket binoculars are bigger and have bigger lens diameters.
However, due to their smaller size they may not be the most comfortable to hold in your hands. If the barrels are too close or the focusing knob is too small they may be more difficult and uncomfortable to use.