Bankers Box for letter and legal documents offers a strong and dependable storage option. Easy setup with FastFold ensures accurate assembly to promote greater strength. Heavier paper makes the corrugated board stronger. Denser packed fluting - the rippled inner core of corrugated board - gives boxes added strength. Uses corrugated board with the two highest-density fluting materials available. Specially chosen print, cutting and folding techniques that leave the fluting layer intact for a stronger storage box.