Filters are an essential part of any black and white photographer's kit, and this set reflects that. The set is made up of Yellow, Red, and Yellowish Green standard filters (not grads). The Yellow and Red filters will enhance the contrast in a sky to varying degrees, while the Yellowish Green both imparts contrast and opens up the tones of green foliage.

11 Yellowish Green Standard
Alters the response of panchromatic emulsions to be equivalent to the eye responding to objects under tungsten illumination.

23A Light Red Standard
Greater contrast effect than No. 21 Orange.

8 Yellow Standard
Darkens sky, cloud and foliage to reproduce correct tones.