Mixing cement and aggregate dry, adding water at the nozzle — lower upfront cost, easier to transport, better for smaller or intermittent jobs and repair work.

Pump pre-mixed concrete to the nozzle — more consistent quality, less dust and material waste, better suited to large-volume, continuous spraying such as tunnel linings.

Switch between wet-mix and dry-mix spraying on the same unit — useful when one project needs both, for example dry mix for smaller repair or patching work and wet mix for high-volume tunnel lining, without buying two separate machines.

Run on their own onboard engine rather than relying on external electricity or a compressed air supply — a practical choice for remote sites or projects without reliable grid power. Worth noting: underground/tunnel use needs proper ventilation for engine exhaust.

Run off compressed air rather than an onboard diesel engine — a good fit where a compressed air source is already available on site, such as underground mines.

Combine a spraying arm with vehicle mobility for large tunnel sections and high-output projects where reach and speed matter most.