Crystal Clear Bags™ traditionally come with a re-seal able top flap which allows the bag to be reopened several times. It's as easy as inserting an item, peeling the adhesive cover strip, and then folding and pressing the flap closed.
The flap seal allows more tolerance than Protected Closure (PC) bags for items to be smaller than the height of the bag as the flap can be folded past the opening of the bag if necessary.
All bags are USPS approved (click here for details). When mailing in plastic envelopes be sure to use self-adhesive stamps. Crystal Clear Bags™ are sometimes referred to as Photo Sleeves.