Barr & Stroud ED PC 8x42 Series 4 Roof Prism Binocular
Barr & Stroud ED PC 8x42 Series 4 Binocular is high-quality, high-precision binocular for the serious observer, the Series 4 ED binoculars from Barr & Stroud are their newest line as well as their top of the range. The ED in their name gives a hint to the main selling point of these Barr & Stroud binoculars and refers the use of Extra Low Dispersion glass lenses. This high-quality, high-precision lenses have less air bubbles and glass deformities in them that are more likely to cause image distortion. So basically the extra low dispersion glass prevents chromatic aberration because it concentrates and directs the wavelength of light more efficiently onto observer eyes.