The PENTAX Papilio 6.5x21 Binocular w/Case (62215) is a part of an optics series called Papilio, the Latin word for butterfly, because it was specifically developed to satisfy the need for close-range observation of butterflies and other insects.
The close focusing capacity of the binocular is in some measure quite limited by the position of the objective lenses themselves, but this particular Pentax has a unique Convergent Lens Optical System Engineering (CLOSE) mechanism which brings the objective lenses closer as the focusing dial is adjusted to shorter distances. The CLOSE mechanism automatically slides the left and right objective lenses toward the center when the focus is fixed at a short distance.
The optics are fully multi-coated to eliminate harmful ultraviolet rays while improving light transmission. This gives you high contrast images with no glare or flare. The Papilio uses high quality BaK-4 prisms to transmit more light at the edges of the field. This enhances the illumination for easier viewing in dim light.
The body is a reverse porro prism design, in which the objective lenses are closer together than the eyepieces. This allows for nearly full-size binocular performance from a very compact body. A soft touch dark grey rubber armor with molded-in thumb grooves covers the durable and lightweight molded polycarbonate body to protect the internal mechanisms and provide a sure grip.
Aside from its manifest virtues as a butterfly binocular, the Papilio is a handy bino for nature walks, hiking, traveling, spectator sports, the theatre, etc. - anywhere compact size, good optics, and light weight are important.