Lightning Powder Zip-Top Plastic Evidence Bags - 100 Bags These self-closing evidence bags can be quickly opened and closed along the zip-lock closure across the top of the bag. These heavy-duty evidence bags are .004" thick and have a large white space on them for ease in writing. Use any ballpoint pen to write the case number, date, time and your name in the white block • 100 Count • 4 mil thick • White, writeable face • Reusable, zip-top seal • Excellent for in-field use • 4 sizes available Size 1 = SMALL: 3" x 5" Size 2 = MEDIUM: 4" x 6" Size 3 = LARGE: 5" x 8" Size 4 = X-LARGE: 9" x 12"