FLAT ONE BLOG. Store important documents safely and with confidence in Bankers Box R Kive Heavy Duty Storage Boxes. Sturdy and reliable, this heavy duty file storage box features triple end and double side and bottom construction to support heavy files without tearing. It has an impressive stacking weight of 850lbs. A deep lift lid with locking tabs stays in place to protect files while the smooth rolled edges help prevent paper cuts. This box features quick FastFold assembly and has reinforced tear resistant