This package contains 100 sheets of 8-1/2 x 11 card stock. The paper is micro-perforated for clean separation into 4 cards per sheet to yield 400 finished post cards. Finished card size is 4-1/4 x 5-1/2. Base stock is 67lb White Opaque Bristol. Copier, Laser, and Inkjet compatible. Compulabel Product No. 410951.