[. . . ] With the purchase of a MB QUART car hi-fi loudspeaker set, you have purchased a technically sophisticated, high-quality product. [. . . ] In the event of serial connection, the impedances of the individual vibration coils will be added, so that no problems need be expected with the load stability of the end unit. section A1 - A3 shows the standard connection , section B1 - B3 the parallel connection and section C1- C3 the serial connection diagram. The accessories to be used (shown on the left) are provided in the enclosed accessory bag. For the connection leads, please use cable with a cross-section of at least 2. Please observe the safety requirements relating to supporting chassis members, the applicable road safety regulations and the instructions of the vehicle manufacturer when installing and using the loudspeakers. Always protect your loudspeakers during installation and use against damage, spray water and overloading. [. . . ] Ensure that the housing is installed firmly and securely, so that it is not dislodged by sudden braking. [. . . ]