<https://dorrfoto.co.uk/products/dorr-go2-b-w-green-colour-filter-318923#product>
<http://schema.org/description>
"Dorr Go2 B&amp;W Green Colour Filter is for creative black and white photography. This filter is inserted into the Go2 Filter Holder for that complete creative effect. Available in other colours.\n\nGo2 Filter System\n\nThe Go2 filter system is made up of a series of different components for your camera and lens. Please see the components below in the order they attach and what they do.\n\n\n\tAdapter Ring - Combines with the filter holder. Available in 49mm to 82mm to match your lens' filter thread size\n\tFilter Holder - Attaches on top of the adapter ring. Holds up to 3x filters\n\tFilter - Up to 3 can be inserted. Use different colours to create different effects or use the Circular Polarizing Go2 filters for avoiding reflections on non-metallic surfaces - also enhances contrast\n\tLens Hood - Can be attached after the filters to avoid reflections\n"
<https://dorrfoto.co.uk/products/dorr-go2-b-w-green-colour-filter-318923>