It is a type of passive transport in which the ions or molecules cross the plasma membrane with the help of carrier proteins and hence the name facilitated transport. It takes place along the concentration gradient and goes not require energy.
It is stereo specific i.e. only one of the two isomers (L- or D-) gets transported across the membrane. The carrier proteins are of low molecular weight. The transport of metabolites by facilitated transport is much faster when compared with simple diffusion.
The entry of glucose into the Red Blood cells (Erythrocytes) is an example of facilitated transport.