"Whiter and brighter images. Simply put, that is the benefit the Everbrite mirror coating. This exotic, dielectric, nonmetallic coating is 99% reflective across the full visual spectrum, resulting in the ""whitest,"" most natural image available. The coating is painstakingly applied to Pyrex with a surface accuracy of a 1/10 wave flatness. The Everbrite is offered in both 11/4"" and 2"" models. The diagonal bodies of each are machined from solid blocks of aluminum. In this way we can insure permanent alignment. The one piece body construction also assures heavy accessories can't force the diagonal body to ""unscrew"" from the barrel as with other brands. Both the 11/4"" and 2"" models feature brass clamp rings, anti-reflection threads and 11/4"" and 48mm filter threads respectively."