Envelopes and heavyweight cards feature natural white paper with a wove finish (25% cotton). Performs beautifully with a broad range of writing instruments including fountain pens. Wove finish supports many types of ink. Packaged in a peggable and resealable box with a viewing window. Cards are 110 lb./297g and envelopes are 24 lb./90g. Acid-free. Box includes 4 1/2" x 6 1/4" flat cards and #6 envelopes. 20 sets/box.