thabasca is a Canadian company specialising in high quality filters for photography enthusiasts. Athabasca square filters are one of the essential peices of equipment required for landscape photography. Manufactured using German made Schott optical glass combined with Nano coating technology, scratch resistant glass, these filters contain a double sided anti-reflective film coating. and use an high quality Low reflections and light reducing layer to help you achieve top quality results. 

This filter provides 6 stops of light reduction.