The Transponder Module is a medium-sized premium part which creates a dynamic Waypoint that is set to the location of the module. It also allows a custom name of up to 12 characters to be shown in the Vehicle list.
Its distance indicator is also a square rather than a circle.
As it is a Premium Part, it can only be unlocked by purchasing it as an add-on. It costs $1.49 USD, $1.69 AUD or €1.49 EUR.