This is a single filter for e Purma Special Camera. It is for use with monochrome films – black and white.

The filter comes is the original box – which is held together with tape.

From the Purma Guide

No. 1. YELLOW: With all pan and ortho films. To darken blue sky either as a background or to show up white clouds. To reduce haze over distant landscapes. To give a natural rendering of greens and yellows in flowers and foliage.