Televue 3.7 Ethos Telescope Eyepiece ETH-03-7 has 21% more AFOV area than the 100° Ethos design. This Televue Telescope Eyepiece permits a nice 62% power increase from a 6mm Ethos, while retaining 68% of its TFOV. The 3.7mm in this telecope accessory actually has more Telescope FOV than our 8mm Plössl, 6mm Radian, and 5mm Nagler Type-6! In 1 1/4" mode, it is parfocal with the wide range of 1 1/4" Tele Vue Plössls, Panoptics, Radians, Naglers, Nagler Zooms, and 6mm and 8mm Ethos eyepieces perfect for your next telescope purchase. Televue has included a screw-on 2" adapter that is designed to make it parfocal with 13mm and 10mm Ethos when they are used in their 2" modes. These features make the TeleVue ETH-3.7 Telescope Eyepiece a wide field of view eyepiece that will open up new visual experiences, from small refractor telescopes to the largest Dobsonian Telescopes.