The Semi-rigid dipole by IBCrazy is for use as both a transmitter and a receive antenna. The dipole has a stiff active element and a flexible counter poise for excellent signal, but flexes to eliminate damage in crashes or when setting your transmitter down.
As a transmitter antenna: This allows for strong polarization match without having to uncomfortably tip your radio upright when making long range flights.
As a receive antenna (Multirotors): Mount the antenna on the receiver on the rear of your multirotor to gain more separation between you critical components.
As a receive antenna (airplanes): Stick the flexible end through the wing so it hangs out the bottom of the aircraft.