100 COUNT OF #4 1/2 GLASSINE ENVELOPES -- 3 1/8 x 5 1/16 INCHES These acid free archival envelopes are made of high quality glassine. They open from the top and have ungummed flaps. Each envelope measures 5-1/16" x 3-1/8". Ideal for all of your philatelic materials. Each order is for a pack of 100.