This is a 1 1/4" eyepiece with an amazing 84 deg. apparent field of view. While much lighter than a 20mm Nagler, it is surprisingly flat to the edge when used on my 8" f10 SCT and on my Orion ST80. It is multicoated and would make an excellent addition to anyones collection of eyepieces. My asking price is $175 plus s/h. If you are looking to purchase a 20mm - 22mm Nagler but are on a tight budget, give this some consideration.