Quality Park Catalog Envelopes, 10 x 13 Inches, Box of 100, White (R4500) 10 x 13 x 1.5 inches 100 ct. Lightweight Tyvek Open End Expansion Envelopes Tyvek is strong and moisture resistant. Convenient Flap-Stik closure requires no moisture to seal. Superior protection for mailing bulky items. Ideal replacement for box or carton. 10 x 13 x 1.5 inches 100 ct. Lightweight Tyvek Open End Expansion Envelopes