Mehrton Summer Series 190. The Mehrton Summer of Series 190 offers a wide selection of international signal tones for the broadest range of applications. It has been developed in the same housing as Series 890, allowing it to be easily combined with up to three signal lights to provide an acoustic and visual solution. 32 tones for versatile applications, adjustable sound output up to 110 dB, 3 tones can be triggered externally, IP65 protection class, brackets for easy combination with permanent signal lights/traffic lights of Series 890.