Museo #6 Standard 4-1/2" x 5-13/16", Two-Sided Matte, Archival Inkjet Artist Cards, 220gsm, 100 Pieces with Matching Envelopes, 14mil. Museo Artist Cards are compatible with most photo-realistic inkjet printers. Museo Artist Cards are made to archival standards: Internally buffered No fluorescent whiteners added Use of naturally occurring pure Artesian well water