The phot r p series blue filter is a special effects filter used when the photographer wishes to add a distinctive blue tint over the entire image it can also be used in conjunction with other phot r filters this filter measures 84 x 84mm and fits our phot r p series holder buy this product by searching b00pw40l8kin the search bar special effect filter for photographersadds a distinctive blue tint over the entire imagefilter measures 84mm x 84mmcompatible with cokinwill fit our phot r p seri