help to identify an old Panagor

I have found an old Panagor lens labelled:

PANAGOR Coated CU +1 49 mm

What means CU +1 ?

I have post the same question on Dpforum, but no replay.

I'm in the processing of ordering the lensmate
, so I need to know which kind of lens I have at home, also if old...


thank you for any help


--
Gian

from Italy

Cu +1

You found a part of the close up (CU) filter set. They come in different strengths +1, +2, +4. Plus one offers just one time magnification.

Polak187, thank you very much for your useful reply