Up for sale is a Denafrips IRIS DDC in excellent condition.
What this does is takes digital inputs like USB and reclocks/cleans the signal so your DAC gets fed the best possible audio signal via a superior output like I2S

Price includes shipping and PayPal fee in the US. International shipping will be a bit more.

I also have a Pontus II 12th Anniversary R2R DAC for sale that makes an excellent companion with this. They were designed to work together.