A4 Self Seal Invitation Envelopes, 4 1/4″ x 6 1/4″, Avocado Green, 250/Pack (4872-27-250) | JAM Paper Discount

Specifies the primary material of the envelope (e.g. paper, plastic, kraft, vinyl, Tyvek, high-density polyethylene, etc.). Tyvek, unlike standard high-density polyethylene (HDPE), is a synthetic material made from HDPE fibers and manufactured solely by DuPont.

Paper weight, stated in pounds (lbs.), is calculated by weighing a ream (500 sheets) of the basis size (master uncut size) of that paper type. For example, the basis size of bond paper is 17″ x 22″ with a ream weighing 20lbs; the basis size of watercolor paper is 22″ x 30″ with a ream weighing 140 lbs.

Describes the location and number of windows built into the envelope. Windows are typically used to show an address that is printed on the contents of the document.