2 7/8" X 3" (73mm X 75mm)

(skirt inkstamp)

Picture courtesy Craig Polkinghorne

2 7/8" X 3" (73mm X 75mm)

(skirt inkstamp) NGK

                       JAPAN

Picture courtesy Bob Berry

2 7/8" X 3" (73mm X 75mm)

(skirt inkstamp)

                       MADE IN JAPAN

Picture courtesy Craig Polkinghorne

2 7/8" X 3" (72mm X 77mm)

(skirt inkstamp)

Picture courtesy Craig Polkinghorne

2 7/8" X 3" (72mm X 77mm)

(skirt inkstamp)

                         MADE IN JAPAN

Picture courtesy Craig Polkinghorne