Kowa enjoys a spectacular reputation of enduring quality internationally, where there are large numbers of nature enthusiasts.
Kowa's 66mm series employ the great features of their world class flagship model, the TSN-821 M, in a smaller scope. Despite having a larger front element than two well-known 65mm scope competitors, the heaviest of the Kowa versions is still lighter than the lightest of their European brethren.
It is entirely a matter of personal preference best determined by experience, but many feel that angled scopes offer a more comfortable position for extended viewing periods. They're usually a bit easier to share amongst multiple users of varying heights as well.
Main lens composed from environmentally friendly, lead-free "eco-glass"
Full multicoatings on all lenses and prisms
360° rotating base with click stops allows usage from many angles-even overhead
Quick-aiming sightline aids in object locating
Sliding sun shade shields unnecessary light and raindrops while providing protection for the front element (which has a 72mm filter thread)
Sealing and O-ring purging which lets you scoff at conditions
Adaptable to 35 mm SLR cameras, digital cameras, and video cameras with optional photo adapter
Metal alloy & carbon fiber rubber-armored construction