1,000 #4 Glassine Envelopes -- 3 1/4 X 4 7/8 INCHES These acid free archival envelopes are made of high quality glassine. They open from the top and have ungummed flaps. Each envelope measures 4-7/8" x 3-1/4". Ideal for all of your philatelic materials. Each order is for a box of 1,000.