End piece

The outermost tip of the sperm flagellum is referred to as the end piece. This region lacks the fibrous sheath, and simply consists of the axoneme wrapped by the plasma membrane. In the most distal segment, the 9+2 doublet symmetry of the axoneme is lost, the microtubules form singlets and are capped to prevent dissolution.

The end piece can be seen as the outermost tip of the flagellum.

Read more about the end piece as a substructure of sperm.