definiens: means all proprietary materials, data or other in formation ( whether or not patentable ) regarding a Party ’s know how, produ cts, business information or objectives, that is de signated as confidential in writing by the disclosing Party, wh ether by letter or by the use of an appropriate sta mp or legend, prior to or at the time any such material, data or other information is disclosed by the disclosing Pa rty to the other Party . Notwithstanding the foregoing, materia ls, data or other information that are disclosed by a Party in writing without an appropriate letter, stamp or leg end, or that are orally, electronically or visually disclosed by a Party, shall constitute Confidential Information of such Party if ( a ) such Party, within thirty ( 30 ) d ays after such disclosure, delivers to the receiving Party a writt en document or documents describing the materials, data or other information, indicating that such materials, data or other information constitute Confidential I nformation, and referencing the place and date of such oral, vi sual, electronic or written disclosure and the name s of the persons to whom such disclosure was made, or ( b ) su ch materials, data or other information are of the type that is customarily considered to be confidential inform ation by persons engaged in activities that are sub stantially similar to the activities being engaged in by the P arties