The sapphire ed 10x43 binoculars feature a high performance optical system with dielectric prism coatings and ed glass to ensure the brightest image possible with maximum clarity and minimal chromatic aberration the rubber armour ensures a comfortable yet solid feel in the hands with plenty of grip this incredible optical performance is housed in a magnesium alloy open hinge design incorporated is a quick ratio 17 turn focus knob low profile multi stage twist up eye cups and stay on lens