To minimize vibration and noise each RCA connector is sealed with anti micro-phony compound to damp excess vibration in that part of the signal path. Helping to enhance the silent background in your system.
The Blue RCA is our entry level RCA given 4.5 stars for sound quality by HiFi Choice in 2012 because we had designed it specifically to work with our Blue speaker cable not as a stand alone product. This we viewed as a failure on our part so put significant time and resources into developing the Blue RCA further and the new version leaves the old Blue in its wake in terms of performance - we are truly proud of it and hope you will be too.
HiFi Choice Review “Excellent in a distinctive way…The Emeli Sandé track shows these cables to be more fluid and mellifluous” Hi Fi Choice July 2013