These are very cool watches. The Gruen Day/Night has a rotating disk that changes all the hour markers black at midnight, then green at noon. This watch is all original and came from its only owner. The case has corrosion on the sides and rear, but on the front and while wearing it looks amazing! We always find these with exterior corrosion. The manual winding Gruen movement is in excellent shape and was just fully serviced an is keeping accurate time. This gentleman wore this watch daily from the 60’s. The original dial is amazingly preserved, as are the original hands. You will see…on the wrist this watch looks fantastic. These are uncommon watches. Priced very well, to sell.