Now, gel filtration chromatography is a technique that uses the size factor of proteins. It can basically separate the proteins based on size. And in gel filtration chromatography, we have this tube, and inside the tube, we have these special beads. And so the proteins move along the tube and through the beads. And the proteins that are largest will move fastest along the test tube. And the ones that are smallest, because they get trapped inside those beads, they will move the slowest.