We make these off-white envelopes using our 100 gsm bookwhite paper. A refined alpha cellulose fibre, lignin free with a 3% calcium carbonate buffering and a pH of 8.5. For complete protection we use a starch based archival quality adhesive and a design which incorporates narrow, round corner, side only seams and a 2 inch (51mm) non-adhesive round cornered flap on the short side. Pack quantity: 50