What is the difference between clamp and grommet mounting for monitor arms?

Clamp mounting grips the desk edge with a C-clamp mechanism — no holes required, easy to install and remove, and works on most desks up to 3.5" thick. Grommet mounting passes a bolt through an existing grommet hole in the desk surface for a cleaner, more permanent installation with no edge clamp visible. Grommet is preferred for desks with pre-drilled grommet holes and for a cleaner aesthetic. Clamp is preferred when the desk has no grommet hole or when the installation needs to be non-permanent. Call OfficeFurniture2go.com at 1-800-460-0858.