Prismatic binoculars with a metal body and a canvas strap. Knobs on each side allow internal yellow filters to be rotated into the eyepieces. The government broad arrow mark appears near each objective lens while the maker's name is inscribed on one of the tubes.

The CF41 was developed as night binoculars for use by the Royal Navy, who adopted it in 1935 as AP1900A. The model was highly successful both in the Navy and in a civilian version, and continued to be made and sold until the 1970s.