JAM Paper and Envelope Recycled Paper Invitation Envelopes are 30 percent recycled made with 24 lb paper with a smooth finish. These envelopes have a booklet opening with a straight flap and gummed seal that makes for easy and clean closure. These classically simple envelopes suit personal and professional mailings with the recipients sure to appreciate your responsibility to help the environment. These envelopes are available in a multitude of sizes and colors and available for purchase in packages of 25.