These premium quality glassine envelopes and bags are made in the USA from transparent virgin 30 pound glassine. They have ungummed flaps and strong seams . These glassine envelopes are the perfect choice across many industries because of their ability to protect their contents with the contents remaining visible through the glassine paper. Glassine envelopes are widely used in the Philatelic, Numismatic, Arts & Crafts, Food, Medical, Laboratory, Seed and Insect Collecting Fields due to their many protective properties: