This is a 1980's vintage Edmund Scientifics 4" f/15 refractor optical tube assembly. It has been upgraded with the addition of a Burgess Optical Model 200A 2" focuser. The objective was recently checked, cleaned, and respaced by Barry Griner at D&G Optical. Optical quality of this lens is exceptionally good. Color correction is also exceptionally good. The original (flaked and scratched) red paint has been professionally removed from the outside of the tube. The tube is now in the white (anodized aluminum) and can be easily repainted by you if you choose to do so, though it isn't at all necessary. The interior of the tube is untouched and is well baffled from the Edmund factory and is a nice dead black. Why pay big bucks for a 4" ED scope when you can get similar performance at a fraction of the price. As a plus, if you're sick of racking the focuser back and forth on your short focus APO as the seeing conditions change slightly, you're a prime candidate for the nice depth of focus of an f/15 scope. $495 plus shipping.