2 7/8" X 4" (70mm X 98mm)

No markings 

Picture courtesy Bob Scafe

3 1/8" X 4" (77mm X 98mm)

No markings

Picture courtesy Dave Dangora

3" X 4" (74mm X 98mm)

(dome inkstamp)

[Verbano]

Picture courtesy Bob Berry

3 1/8" X 4" (77mm X 98mm)

(dome inkstamp)

{Richard Ginori}

Picture courtesy Bob Berry

3" X 4" (73mm X 98mm)

No markings 

Picture courtesy Bob Berry

3" X 4" (73mm X 98mm)

No markings 

Picture courtesy Bob Scafe