Characterized by an in-line, external snap-on sealing module.
Position the envelope, one at a time, with the flap under the sealer tongue/brush and manually slide forward until the machine engages.

Characterized by an integrated sealing module with a side-guide, an auto-start / stop sensor and a seal / no-seal selector.
Position a handful of envelopes in the side guide and fan-feed while the machine automatically power feeds each envelope.
Operator must stop feeding envelopes to remove out stacked envelopes.
Significantly faster throughput than manual feed.