Difference Between Metal-In and Metal-Out ESD Bags

In previous blogs, we’ve discussed how important it is to take care of sensitive materials and devices by ensuring that your work environment is ESD safe. Today we’re going to dive into the differences between two commonly used ESD protection bags- the metal-in and metal-out bags.

Both types of bags are conductive, or metalized, and comprised of multiple layers that make up a protective shield. The protective shield works to keep electrostatic discharge generated by surfaces, other materials and the user from making contact with ESD sensitive devices. With that being said, both are different in their overall makeup as well as their best uses and features.

The more commonly used of the two is the metal-in shielding bag. Like it’s name would suggest, metal-in bags feature a metal shield closer to the middle, or inside, of the bag. The metal shield lies within a layer of static dissipative polyethylene and polyester. Typically speaking, the metal-in bags gain the edge when it comes to cost and durability. They last longer than metal-out bags as they are less likely to scratch and they’re more commonly found on the market.

In metal-out bags, the layer of metal is closer to the outside surface of the bag in between the polyester and the abrasion resistant coating. Because of this, this type of bags have a lower resistance reading and can dispel a static charge faster than metal-in bags can. They’re most commonly used in critical electronics applications and disk drive manufacturing and are most recommended for operations where faster charge decay is preferred.

While there’s no direct answer to which type of bag you should buy, it will depend on your budget, the materials you use and the types of operations you perform. If you have any additional questions about metal-in and metal-out bags, be sure to give us a call. You can shop our inventory of ESD protection bags here.