The 9 Best Size 9 Envelopes (2023 reviews)

The amazon basics size 9 envelope is capable of outshining several other envelope featured in this list in overall features. The quality of the envelopes is good. It is great for sending out quickbooks and printed checks. It includes confidential account or client information, the envelopes feature plastic windows and an interior security tint that prevents documents from being read through the envelope when held up to the light. The glue holds well and the flaps stay securely down. The security feature helps when passing them out during the first week of school, so kids wouldn't poke around in other people's envelopes.

It comes with the ceiling strips, which will save more time. It is a function of where simply prints the vendor's name and address.

Why We Like This:

Great quality and value for a small business
Thick enough for strength and privacy
Fits the standard sizing and window placement
Enveloped and are intended for invoices and statements but not cheques

Best For company: Blue Summit supplies Self Seal

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The blue summit supplies self seal is the best reliable envelope on the market today. These are the best value laser printer compatible envelopes you can get. They hold the address labels in place without allowing them to peel away. It is easy to seal and envelopes are secure when sending checks. The box they come in is great also.

These envelopes are designed for both laser and inkjet printers. The security lining is great, it obscures confidential contents perfectly. The stickiness of the self-seal is better than the OfficeMax. They are envelopes, seal well.

Why We Like This:

Nice and bright white security envelopes with good self stick strip
Good quality and seal really well
Delivers what they promise

Best For Check: Aimoh super Secure Seal

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The aimoh super secure seal is suitable and reliable and fits well with your regular usage. These envelopes are professional looking and simple to stuff and seal. It comes off with the strip, leaving gaps in the seal. It can tear and or melt with certain machines. This one really makes a firm seal. The self-seal makes it so easy and efficient. It is perfectly for quickbook generated checks. These are more suitable for sending out invoices.

Why We Like This:

Seams good, windows good, seals good
Perfect for quickbooks invoices and statement’s
Sticky, gummy glue residue all over your hands

Best For Mailing Invoices: HERKKA Size 9 Envelope

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Herkka offers a variety of envelope for personal choice and yet maintaining quality in all the variants. These self stick, security envelopes are perfect for QuickBooks invoices. It is designed with peel & seal closure—no moisture needed and a premium security tint to protect sensitive information and a super strong self-seal strip. It works well with invoicing and other mailing needs.

It is superior to any self sealing one with a strip. There is no need for extra glue or tape to seal it. It is great for sending off letters. The envelope seals well but you can still open it (carefully) if you accidentally seal it.

Why We Like This:

Good brand reputation
One of the new comers and featured product

Best For Your timeline: Quality Park Size 9 Envelope

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Redi-strip envelopes increase efficiency with removable strips and adhesives that seal without moisture—simply peel and press. The whole point of two-window envelopes is that the paper inside provides the information, so you don't print on the envelopes themselves. These security envelopes have a reflex blue pattern to protect sensitive information, even when envelopes are held up to light. The unique double flap design allows you to simply raise the lower flap and press to seal.

These business envelopes are made of 24 lb white wove paper with side seams for a professional appearance. These are of good quality and the pre stamped closure is the best. A special redi-seal closure doesn't require any moisture to seal. It is perfect for quickbooks invoices.

Why We Like This:

Makes stuffing envelopes a lot easier and quicker
Security-tinted window and double-window envelopes to fit billing statements, paychecks and receipts
Good investment for long term

Best With postage stamp: Aimoh Size 9 Envelope

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These are perfectly adequate envelopes. It is manufactured from heavyweight extra white sturdy wove stock paper, combining a professional security tint pattern and smooth finish. The durable, woven paper extends the tampering resistance of this envelope, standing up to normal postal wear and tear without damage, perfect for documents and sensitive correspondence.

These envelopes use an adhesive similar to the postage stamp. The peel off strip comes off easily and the adhesion sticks well. It is made to match the greeting card. The envelopes also have a pattern printed on the interior, so that the contents of the envelope cannot be readily read through the paper, providing additional security for your mailing. They are the perfect #9 Size, and you can not see anything that is inside.

Why We Like This:

Privacy is assured, with privacy screening on inside
Paper is thick enough to inspire confidence
Smaller than common #10 envelope, convenient, well made, good value

Best For letter: Blue Summit supplies Size 9 Envelope

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We would, of course, be remiss if we didn't mention blue summit supplies size 9 envelope for daily purpose. These envelopes are designed for both laser and inkjet printers. It is the safest type of envelope, with no chance of confidential information showing through windows. It is great for quick quantity machines. The Dark black security tint lining is completely opaque and blocks others from seeing your documents.

These envelopes work great and are much more cost efficient than other brands. It provides complete mail security to add to that it is perfect for secure everyday home and business mailings. The Thick and durable 24 lb white paper stock that completely protects your contents during transit, with no need to worry about it tearing during transit.

Why We Like This:

Like the ability to seal without moisture
One of the new comers and featured product

Best For Laser Printer: Endoc Size 9 Envelope

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Secure mailing of both light and bulky documents and durable lightweight envelopes each envelope offers you unrivaled reinforced construction for extra strength and rigidity. It fits great when inserted in the #10 standard envelopes and return envelopes and more. The pack of 50 also gives you better value for your money, making them ideal envelopes for both home and office use.

These are made from thick 24lb white paper, which means they have better resistance to punctures, moisture, and all kinds of stress that come with the mailing process. It comes with a conveniently easy-to-use self-sealing flap with an ultra-strong adhesive that creates a secure tamper-proof seal. It is also moisture resistant, preventing chances of opening the seal with steam.

High-security envelopes each envelope contains several unique features that help keep your mail private and secure from prying eyes throughout the mailing process. The envelopes' windowless design also makes them secure by eliminating any chances of your confidential information showing through the windows.

Why We Like This:

New and hot release
Lot of satisfied buyers

Best For Other confidential documents: PANDRI Size 9 Envelope

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Best part: pandri size 9 envelope costs comparatively low and it is available to ship in 24 hours. Sending and mailing addresses can be clearly displayed for standard business and legal mailings, advertising campaigns etc, reducing the hassle of handwritten addresses, top window. It has 500 quality #9 double window envelopes for a long lasting supply, perfect for bulk mailings. It fits with no creative folding. It has this design that makes it quicker and easier to send more invoices,just peel and press without the need for glue sticks and licking envelopes, a huge time save.

These envelopes are the right size and the windows are in the perfect location for these invoices. They are security envelopes with the priming on the inside. It has the plastic film on both spots.

Why We Like This: