Heavyweight folded or flat correspondence cards (110 lb, 297gsm) with matching envelopes (24 lb, 90gsm) feature beautiful, natural white paper that delivers the ultimate handwriting experience. Matching natural white envelopes contain 25% cotton and are acid free. Personalize your messages with a special touch on beautiful, reliable Strathmore paper that is compatible for pencil, pen, charcoal, calligraphy or any other medium. Send a beautiful, elegant letter every time with Strathmore 500 Series Writing Cards. Each pack includes 20 cards and 20 envelopes.