These Alvin Blueprint Ship Bag 9.5X33 100 shipping bags use .004 mil. of polyethylene to protect blueprints from the moisture, dirt and tears that they would be vulnerable to without a tough shipping bag to protect them. With this inexpensive packaging option, your blueprints can be shipped through the USPS, FedEx or UPS. Use labels on these bags and mark them with pens or black markers. These shipping bags are specially formulated to accept all of those labeling methods. You can close each of these 100 shipping bags with either staples or any type of tape. With your blueprints safely in one of these tough shipping bags, they will be safe from the scrapes that come from being dropped, from spills and from rain ruining the drawings you've made.