The 8-24mm Zoom eye piece comprise 8 lens elements in 6 groups, with 5 of the elements made from premium optics. Eye relief is a comfortable 15mm to 18 mm through the zoom range. The apparent field of view ranges from 40° at the 24mm setting, to a wide 60° when set to 8mm. The 1.25" eyepiece barrel is tapered to prevent accidental slip-outs, and is threaded for use with 1.25" filters. The quoted price is only for single piece.