White Block Reclosable Poly Bags are great for keeping track of small items. Bags feature a single-track zipper along the width of the bag. Zipper helps keep products secure. White block area allows important information to be written on the bag. White block area works great with pens. Bags can be reused and do not require labels. Bags meet both FDA and USDA requirements. Bags are 2 Mil thick. Inside usable dimensions are 4 x 5".