There are many different varieties of plastic bags used for packaging. Often these bags are resealable bags so that they can be used more than once, or so that the items included can be taken out, used or read, and then put back inside the plastic for safe-keeping. Here are some of the more common types of bags used with a small description of each type. Please note that these are basic types of bags, there are also many modifications and customizations that can be made to each type.
Anti Static Bags: These are often used for packaging electronic equipment. An additional anti-static additive is added to the plastic which disperses any static electricity. They are usually not designed for long term storage but are great for packaging computer parts and other electronic components that are soon to be sold or otherwise distributed.
Flap Lock Bags: These are also known as sandwich bags, and are used primarily for lunches, sandwiches and food storage. These are frequently sold pre-packaged in easy to get to cardboard containers. These type of bags have a folded back lip of plastic that is sealed on either side. This lip can be flipped over to seal whatever is inside the bag. While they do a fairly good job of keeping the item inside the bag they do not totally seal the bag off. Air and moisture can still get inside the sealed bag.
High Density Polyethylene Bags: These bags are specifically designed to be both moisture and vapor resistant, thus they are great for sealing items that are damaged or spoiled by moisture. They are also non porous so nothing will either get in or out of the bag.
Metallocene Bags: Similar in quality to high density polyethylene bags, these particular bags are also puncture resistant which makes them ideal for packaging sharp, pointed or jagged objects.
Polypropylene Bags: This type of bag is stronger than the polyethylene bags and it is also harder and more rigid, not as bendable. Moisture resistant and non porous, this type of bag can actually withstand very high temperatures as it does not melt.
UVI Resealable Bags: The plastic is treated with a UV inhibitor, making this type of bag the perfect choice for anything that is easily damaged by sunlight. Great for storing items that need to be on open shelves.
Aside from these basic different types of plastic resealable bags, there are also a number of other modification and customizations that can be made according to specific instructions and needs.