Cromofilter SA is known as a producer of filters. It was later renamed Cokin SA.
Cromofilter SA was founded in 1973 by freelance fashion photographer Jean Cokin to distribute the Cokin Creative Filter System.
Cokin filters are a series of square filters which fit into a stackable filter holder. An adapter, sized for each lens, attaches the holder to the lens. This way one set of filters can be shared across lenses with different filter ring sizes. There are also adapters that can be attached to the tripod mounting point of the camera, with thumb screws on the outside of a lens, or with magnets.
The lenses come in four series: A Series (67mm), P Series (84mm), Z-Pro Series (100mm 4-inch), and X-Pro Series (130mm).