Single 8 Mil Inkjet Gloss 4" x 6" Flat Card Invitations. These cards can be used as response cards, invitations or postcards. Made from an 8 Mil (195 gsm) Inkjet gloss cover stock. Optimized for HP Inkjet Printers but works great with almost any inkjet printer brand. These cards are Inkjet printer compatible only! One side gloss, one side matte - both sides printable!