INJECTION UNIT FOR ADMINISTERING OR DELIVERING A FLUID PRODUCT

The invention relates to an injection unit, preferably a pen-shaped injection unit, for administering or delivering a fluid product. The injection unit comprises a housing, an axially movable piston rod mounted in the housing in a non-rotatable manner, a delivery apparatus having a threaded nut that is able to move the piston rod in order to deliver product, a dosing device having a dosing sleeve, a rotary knob, a discharge button arranged coaxially on the dosing sleeve, and a receptacle for the product. The dosing device is connected to the delivery apparatus via a coupling mechanism, wherein the coupling mechanism includes of at least two coupling surfaces that each carry a toothing comprising teeth, wherein the coupling surfaces are used to generate an acoustic and/or tactile signal corresponding to the set or corrected dose of the product to be administered during the dosing operation or during correction of the dose.