JAM PAPER #7 Coin Tyvek Tear-Proof Open End Envelopes - 3 1/2 x 6 1/2 - White - 50/Pack Durable Tyvek Envelopes - White Size: #7 Coin (3.5 x 6.5 inches) Quantity: 50 Envelopes per Pack These tyvek envelopes are very durable and much more tear resistant then regular paper envelopes. These envelopes are 10% recycled, have a commercial flap, and a semi-smooth textured finish. These Tyvek Envelopes are made out of the same tyvek material that helps insulate houses, making them very durable! Use these for all of your important personal or business mailings, or around the home and office!