(Perforation Varieties) 1¢ Blue, "Skinny" Perforation, double vertical perforations and separated at both sides along the inner perfs resulting in an extremely narrow stamp, boldly tied by three bold strikes of four-rings cancel on immaculate orange buff cover to Pottsville Pa., docketing at left, probably a drop use since flap originally sealed, Extremely Fine and choice. Scott No. 63 var.  Estimate $500 - 750. THE FAMOUS "SKINNY" STAMP USED ON COVER SHOWCASING THIS REMARKABLE PERFORATION ERROR. $0 (Image)