This metal grill protection was precisely designed for the A17-M model.
The grill covers the whole front side of the speaker to make sure that both transducers could not be damaged.
The acoustic design of the grill provides a maximum alteration of 1dB on certain high frequencies. The global acoustic performance of the product remained then almost unchanged.
The mounting of the grill requires precision, but the process is quite simple and detailed in a Mounting Manual delivered with the grill. Read the manual carefully before installing the grill to avoid any mishandling.