Abstract: An envelope opening apparatus for mail assembly operations which employs timed intermittent bursts of compressed air or other gas. One or more gas jets are used in association with an inserter arm, and envelopes are sequentially conveyed past the inserter arm and gas jets. As each envelope is positioned adjacent to the inserter arm and gas jets, a controller computer activates a control valve, supplying compressed air to the gas jets, which direct a blast of air at the envelope, opening the envelope to form a pocket suitable for insertion thereinto of mail materials.