M46x0.75 Filter - Yellow 1.4x

I don't know what lens it was purposed originally. But it can be used with any lens that has 46x0.75 filter thread.

Used condition, needs some cleaning.

Yellow filters are used to shoot sky usually. It helps to distinguish clouds more clearly. Basically, it makes red, orange and yellow colors more bright, but makes blue and cyan color darker. So, it helps to render objects against clear blue sky with higher contrast.