#10 Envelope – 10.48 cm x 24.13 cm

The #10 envelope is the standard choice for business correspondence. Its elongated format easily accommodates a 21.59 cm x 27.94 cm (8.5" x 11") sheet folded into thirds. It is widely used for everyday commercial and administrative mailings.

Ideal for:

• Business letters

• Invoices

• Statements and notices

• Direct mail campaigns

Key features:

• Traditional flap for secure sealing

• Window options available to display the recipient’s address directly from the enclosed document

#9 Envelope – 9.84 cm x 22.54 cm

Slightly smaller than the #10, the #9 envelope is most commonly used as a return envelope included within a larger mailing. It is also suitable for sending smaller documents or forms.

Recommended uses:

• Return mail

• Reply envelopes

• Small documents and forms

Main characteristics:

• Designed to fit inside a #10 envelope

• Often pre-addressed for convenient responses

#6 3/4 Envelope – 9.21 cm x 16.51 cm

The #6 3/4 envelope is ideal for compact mailings. It is frequently used for checks, receipts, or short messages in both professional and personal settings.

Suitable for:

• Checks

• Receipts

• Short notes

• Small forms

Advantages:

• Compact and practical format

• Can be inserted into #9 or #10 envelopes for combined mailings