Tyvek File Pockets provide extra durability to protect your important letter-size documents. Extra-durable front and back covers hold large, bulky files and small loose items. Gussets expand with project needs. 3-1/2" expansion holds up to 800 sheets. Fully lined, Tyvek-reinforced gussets with added rollover feature provide wear-resistance and tear-resistance. Full-length tab on the back cover provides room for labels or handwritten titles. Front flap folds down for easy access.