This is the highly prized Dallmeyer Pentac 254mm 10 inch 2.9 high speed lens.  This lens is the sought after portrait lens that is incredible for wet plate collodion or mounting on a 5x7 Graflex home portrait or 4x5 Graflex Super D and other 4x5 Grflex SLR cameras. It's ideal as a close portrait lens on 4x5.  This is a later version that is coated and formulated and sold as a camera lens not an aerial lens.  Serial number 772104.  This lens is one of a group of identical lenses which were never used.  There is very slight haze on one element which could potentially be cleaned but has not affected any of the images I have shot with (using one of the other lenses from the group). The coatings are in beautiful condition. Cosmetics are pristine. The iris works and is smooth.  Contrast from the lens is beautiful and no softness or glare.  This lens will cover 4x5, 5x7, and 8x10 with some vignetting.  There is no flange included but there are a number of machinists who will make this including S.K. Grimes in Rhode Island.  Aside from the slight haze the glass is in superb condition. Comes with original front and rear lens caps.