Flagella have 3 parts i.e. basal body, hook and filament.
The basal body is a rod-like structure having ring-like swellings and embedded in the cell envelope. There are two pairs of rings L and P (in the cell wall) and S and M (in Cell membrane).
The hook is curved structure attaching the basal body to the filament.
The filament is a long tubular structure composed of the protein flagellin.
Bacterial flagella perform rotation type movement that brings backwards pushing of the water.
There are two pairs of rings L and P embedded in the cell wall.