The USB 2.0 Gender Changer A F - A F is a type A socket to type A socket for coupling type A plugs together.

The USB 2.0 Gender Changer A F- B F is a gender changing coupler used to couple a type A male and a type B male together.

The USB 2.0 Gender Changer A F- B M is used for converting a standard type A plug into a type B plug for use with devices such as USB 2.0 printers, scanners etc.

The USB 2.0 Gender Changer A M - B F is a gender changer for changing a type B male into a type A male or use on devices with type A female sockets or vice versa.