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White #10 security envelopes, 500 pack, self-seal, blue tint interior

Columbian COLO151 #10 Security Envelopes 500 Pack Self Seal 4.125 x 9.5 in 24 lb White

SKU CH-Z5YF-CHKZ6 MPN COLO151

Standard #10 size holds folded letters, blue security tint protects confidential data, and peel-and-press self-seal closure speeds bulk mailing of 500 envelopes

  • Product typeCOLO151
  • Product colorWhite
  • Size details9.5 in × 4.125 in × 0.1 in
  • Pack quantity500
  • Blue security tint shields confidential documents from view
  • Peel-and-press self-seal closure removes the need for moisture
  • 24 lb white wove paper gives a crisp professional feel
  • Standard #10 size fits letter sheets folded into thirds
  • Bulk box of 500 envelopes keeps mailrooms stocked

Standard #10 Size for Business Mail

These Columbian COLO151 envelopes measure 4.125 x 9.5 inches and hold letter-sized sheets folded into thirds. The pack contains 500 white envelopes made from 24 lb wove paper with side seams. A blue security tint and interior safety pattern block visibility to protect confidential contents. The self-seal closure uses a peel-and-press adhesive strip.

Check Document Fit and Sealing Preference

Verify that your standard 8.5 x 11 inch documents fold neatly into thirds for the 4.125 inch width. Confirm the self-seal adhesive suits your workflow instead of traditional moistened gum. The envelopes have no window, so addressing must be printed or written directly on the face. Ensure 500 units matches your storage space and mailing volume.

Consistent Performance Across High-Volume Runs

The 24 lb paper weight maintains rigidity through automated folder-inserter equipment and repeated handling. Self-seal adhesive retains tack across the full 500-count box without drying out during extended use. Security tint remains effective after stacking and transport. Side-seam construction resists splitting when envelopes are filled to capacity.

How it compares

Measured against everything we stock in Document Envelopes & Pouches, at today’s prices. Recalculated every night.

Price $27.99
Cheaper than about 83% of the 638 comparable items (median $61.99).

Specifications

Product
Brand nameColumbian
Model nameCOLO151
Product typeCOLO151
Product colorWhite
Size & build
Size details9.5 in × 4.125 in × 0.1 in
In the box
Pack quantity500

Questions about this item

What comes in the box and do I need anything extra to seal them?

The box contains 500 white #10 envelopes with a peel-and-press self-seal strip, so no moisture or separate adhesive is required.

Which size and paper weight should I choose for standard business letters?

These are the standard #10 size at 4.125 x 9.5 inches and use 24 lb wove paper, matching typical folded 8.5 x 11 inch documents.

How well does the blue security tint hide confidential text once the envelope is sealed?

The interior blue tint and safety pattern block visibility through the 24 lb paper, even when held up to light, protecting invoices or checks inside.

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