Static Shielding Bags — StratoGrey™ Seal Top ESD Bags

A static shielding bag is a packaging bag that forms a Faraday cage around its contents, blocking outside electrostatic discharge from reaching the electronics inside. StratoGrey™ bags do this with a dual coating of conductive thermoplastic resin over a polyethylene film rather than a metal foil layer, so there is no metallized layer to crack or flake. They are used for circuit boards, integrated circuits, hard drives, memory modules and any component with an ESD sensitivity rating.

Anti-static bags (the pink ones) only keep the bag itself from generating a static charge as items slide against it, and they do not stop a discharge from outside the bag. Static shielding bags like StratoGrey™ add a conductive layer that blocks external ESD events from reaching the contents. Use pink anti-static for non-sensitive parts, hardware and general benchtop storage; use shielding bags any time a component carries an ESD sensitivity classification.

Yes. The bags in this category are seal top bags, meaning they have a press-to-close track at the opening that you can open and reclose by hand as many times as you need. That makes them practical for service work and kitting where a part goes in and out of the bag repeatedly. If you want a one-time tamper-evident closure instead, the same bag can be heat sealed shut below the track. Open-end shielding bags without a seal top are also available; check the individual size listing.

Run your fingers along the full length of the seal top track and check that both ends are closed, because a partly open corner defeats the shielding. For shipments where you want evidence of tampering, add an impulse or constant-heat seal across the bag below the track, or seal the bag with an ESD-safe label that must be broken to open. Do not staple a shielding bag; the staple punctures the conductive layer.

Measure the widest and longest points of the item, then add about 1" to the width and 2" to the length so the part sits fully below the closure with no strain on the seams. A standard 12" x 9.6" ATX motherboard fits comfortably in a 12" x 15" bag; a 3.5" hard drive fits an 8" x 10"; small ICs and connectors are usually bagged at 4" x 6" or 6" x 8". For boards with tall heat sinks or connectors, measure the diagonal instead of the flat dimensions.

Yes. StratoGrey™ bags use an amine- and amide-free interior, which matters because amine-based antistatic additives can cause stress cracking and hazing on polycarbonate housings, lenses and light pipes. That makes these bags appropriate for optical assemblies, display bezels, medical device enclosures and anything else with a polycarbonate surface in direct contact with the film.

Outgassing is the slow release of volatile compounds from a plastic film, which can condense on optics, contacts and sensor surfaces during storage. A low outgassing bag releases very little of that residue, so it will not fog a lens or leave a film on gold-plated contacts. This is why StratoGrey™ is specified for cleanroom, semiconductor and medical device packaging as well as general electronics.

Yes. The grey exterior takes permanent marker cleanly and accepts pressure-sensitive labels and printed tags. Write on the bag before you load the component so you are not pressing a pen against the part through the film, and keep labels on the outside, since adhesive inside the bag can leave residue on the contents.

No. StratoGrey™ bags control static only. Polyethylene slows moisture but does not stop it, so for moisture-sensitive devices (MSL-rated surface mount parts, long-term storage, humid warehouses or overseas freight) you need a foil moisture barrier bag sealed with desiccant and a humidity indicator card. See our LK Packaging Barrier Bags for that application.

Static shielding bags of this type are commonly specified inside ANSI/ESD S20.20 and IEC 61340-5-1 ESD control programs, and MIL-PRF-81705 Type III is the usual military specification for non-metallic shielding packaging. Conformance is certified per product and per lot rather than per category, so if your contract calls out a specific standard, contact us for the current test reports on the exact size and part number before you order.

Yes. The conductive coating is thin, and heavy creasing, scuffing, punctures or repeated crumpling can break its continuity so the bag no longer shields reliably even though it still looks intact. Inspect bags before reuse and retire any that are wrinkled, scratched, torn or have a damaged seam. Most shops treat a shielding bag as good for a handful of handling cycles and use a fresh bag for anything shipping to a customer.

Generally no. The conductive coatings make these a multi-layer film, so they are not accepted in curbside recycling and not accepted at grocery store polyethylene film drop-off either, where they would contaminate the stream. Reuse them in-house until the coating is damaged, then dispose of them as regular waste unless your hauler or a specialty electronics packaging program will take them.