JAM PAPER booklet invitation envelopes are crafted from 32-lb linen paper with an acid-free, high-quality linen finish. A moisture-activated gummed seal provides a secure closure for mailing invitations, announcements, RSVP cards, greeting cards and business mail. The envelopes contain 30% recycled content (Post Consumer Recycled Content Percentage: 30%) and are part of the recycled booklet envelope product line; they are not water resistant. Packs are sold with 25 envelopes per pack. Contains Recycled Content - See Specs for Details.