# Audible fire alarm systems powered by compressed gas — Postal shipping restrictions by item category

For Audible fire alarm systems powered by compressed gas, carrier is USPS; restriction type is restricted; scope is domestic mail via surface transportation; conditions is Acceptable via surface transportation if comply with conditions in Packaging Instruction 2E, recorded from its source on 2026-08-04.

- **Item category:** Audible fire alarm systems powered by compressed gas _(unconfirmed — we could not tie this to the quote below)_
- **Carrier:** USPS _(our reading, not quoted from the source)_
- **Restriction type:** restricted _(our reading, not quoted from the source)_
- **Scope:** domestic mail via surface transportation _(our reading, not quoted from the source)_
- **Conditions:** Acceptable via surface transportation if comply with conditions in Packaging Instruction 2E

## What the source says

> Audible Fire Alarm Systems: These systems, if powered by compressed gas, are acceptable in domestic mail via surface transportation if they comply with conditions in Packaging Instruction 2E

## Source

- https://pe.usps.com/text/pub52/pub52c3_021.htm

Last verified: 2026-08-04. Review by: 2027-08-04.
Part of [Postal shipping restrictions by item category](https://referencesource.org/shipping-restrictions-by-class/).