Designed for repeated use, double prong metal clasp is durable and eyelets are reinforced Constructed from heavyweight 28 lbs. stock designed to give contents extra protection during mailing, storage and handling Feature a moisture activated secure seal with deep gumming on the flap to create a permanent seal Reusable, so you can substantially reduce purchasing Heavyweight brown kraft stock protects contents during mailing, storage and handling Unmarked and smooth, the windowless surface has plenty of space available for labeling, printing and writing