The insulator on the left is embossed on the front: PATENT / 504 / PENDING Very pretty glaze! I have some pin types with an identical glaze, and those are unmarked. It measures 3 3/4" long and 2 3/4" tall. The one on the right is embossed WHITE'S / 504 This one has three glaze rest bumps on the base. Decent color. It measures 3 7/8" long and 2 3/4" tall.