GRABO High Flow
More flow, so the pump can out-run a leaky surface.
Flow versus vacuum
Two numbers describe a vacuum system. Depth of vacuum sets the maximum force on a perfect surface. Flow rate determines whether that vacuum can be maintained on an imperfect one.
A High Flow system moves more air per unit time, so it can hold a working vacuum against a larger leak — which is precisely the situation on textured or slightly porous construction surfaces.
Where it fits
Rougher, more textured or marginally porous surfaces where a standard pump cannot keep up.
It does not make a genuinely porous material attachable — see porous vs non-porous.
Related
See the vacuum pump for the underlying principle.
Questions about this
What does High Flow change?
Air volume moved per unit time. That lets the pump maintain a working vacuum against a bigger leak, which is the situation on textured or marginally porous surfaces.
Does it work on genuinely porous material?
No. Higher flow extends the range of marginal surfaces; it does not make an open-pore material sealable.