The Ultra Diamond is equal to the Reference, but uses 2.9 mm twisted pairs for all types and so uses twice the core material. The twisted pair topology further reduces sensitivity to RFI and EMI signals as where the doubled core material lowers micro-distortion even further. In addition to the qualities of the Reference, the Ultra delivers an ultra-black background to the music. The Ultra Diamond is slightly less easy to handle but is easier to work with and to look at than many other cables in this class. The proprietary silver-gold alloy has the lowest micro-distortion in its price. Every Crystal Cable comes with a laser engraved serial number and a certificate of authenticity.