Envelopes 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. 24 lb./90g. Acid-free. #9 envelopes measure 3 7/8" x 8 7/8". 25-pack.