7x Magnification is the marine standard, with a wide, stable image for tracking other boats, buoys and bridge numbers even in rough water. High Contrast Optics provide bright, sharply contoured images with natural color definition for outstanding viewing quality suitable for both beginners and professionals. Floating Prism System uses flexible silicon lens mount to absorb severe shock, impact and abuse without damage. Sports-Auto Focus™ Systemlets you focus each eyepiece to your vision once, then keeps images razor sharp from 20 yards to infinity. No more chasing focus on moving objects. Makrolon® housing is durable polycarbonate with NBR Long Life rubber armouring, creating a lightweight, rugged chassis that withstands 11 Gs of impact. Impervious to harsh conditions for generations of trusted use. Nitrogen injection system seals 14-psi pressurized dry nitrogen into the optic, for fog-proof clarity in any condition.