<https://subwaystamp.com/products/glassine-envelope-1-1000#product>
<http://schema.org/description>
"Made from transparent virgin 30# glassineWith ungummed square flapsStrong seams, using anti-tarnish adhesiveSize: 2 7/8 x 1 3/4\"square flap"
<https://subwaystamp.com/products/glassine-envelope-1-1000>