No #3 Glassine Envelopes. Size: 2 1/2 X 4 1/4 “”. Pkg. Of 100. All envelopes are made from the best, transparent virgin 30# glassine to assure maximum visibility. Ungummed, folded down flaps with strong seams, using anti-tarnish adhesive which will not affect contents. Smooth cut edges to insure that perforations will not be harmed.