Mail checks, invoices, and letters. These standard #10 envelopes will hold documents printed on 8 1/2" × 11" paper.

To close envelopes with a gummed seal, moisten the seal and press it shut.

Close envelopes with a strip seal by pulling off the paper strip and pressing the envelope shut.

Envelopes with diagonal seams pass smoothly through high-speed mail-inserting equipment, while envelopes with side seams are more likely to get jammed.

Envelopes with a security tint keep letters confidential while they pass through the mailing system.