Dana took care of it and launched the confidence signature series, citing many advanced technologies of the 30th anniversary "Sapphire" speaker, which greatly improved the signature series from the inside out. The new series includes confidence C 1 signature, confidence C2 signature, confidence C4 signature and confidence center signature, which is positioned in the advanced speaker market. On the back of each speaker, there is an aluminum back plate engraved with the signature of Wilfried Ehrenholz, founder of Dana, to show its uniqueness.