The catalogs at Cameraeccentric.com and the Lens Vademecum indicate that the Verito was an ƒ/4 lens except for the two smallest sizes, denoted A and B, which were ƒ/6. The A is a lens of 5" FL and was intended for 3 1/4 x 4 1/4. I have a 5" Verito, presumably the A since that's the only 5" lens listed. However, my 5" Verito is clearly marked ƒ/4.5. I have checked the focal length and the entrance pupil and the numbers check pretty closely.
But I cannot find any information on a 5" ƒ/4.5 Verito. Hence the enigma. Does anyone have any information or insights to offer? I can only assume that it must be a one-off or perhaps a prototype unless it was one of the "special Verito" lenses alluded to at Antique and Classic Cameras,
"Over time "Special Verito" lenses were even produced for small format cameras."
This lens is mounted in a Betax #2 shutter which looks to be a factory mount, although I can't be certain of that. Perhaps it was made for a specific camera, then re-mounted in the Betax. Curious.