Rare Clave Paris 1.25” Barlow. I purchased this new from Cross Optics in 1979. The 5” long tube, by Cross Optics, is delrin and relies only on friction to hold the eyepiece. Because there isn’t a lock screw it isn’t quite suitable for today’s heavy eyepieces. It is a wonderful Barlow for planetary eyepieces. The lens is in pristine condition.