9.5 x 12.5 Booklet Envelopes - 28lb. Bright White - Pack of 100 100 Booklet Catalog Envelopes Each measure Size 12.5 inches across 9.5 inches tall. Color bright white - These heavily gummed flaps produce a secure seal. a great way to send flat but bulky materials excellant for magazines, or catalogs, pamphlets, brochures, sales literature, booklets, annual reports.