What are the different sand paper grits available for sanding various surfaces?

Sandpaper grits range from coarse (around 40-60 grit) for heavy sanding and removing material, to medium (around 80-120 grit) for general sanding and smoothing, to fine (around 150-240 grit) for finishing and polishing surfaces. Ultra-fine grits (above 240) are used for very fine finishing work.