Fizik Terra Argo X3 Saddle - Kium 160mm BlackFizik Terra Argo X3 Saddle Kium 160mm Black. The Terra Argo X3 is a ride compliant gravel specific saddle with a short nose design and generous ischial support for improved stability featuring a carbon reinforced nylon shell and Kium hollow rails. Argo: versatile short nose saddle that encourages stability and relieves pressure on sensitive areas X3: A combination of a ride compliant carbon reinforced nylon shell and a Kium hollow rail with a high