Central plug made of OCC copper coated with a rhodium layer subjected to the Alpha process. Fixing the cable with soldering. Screen mounted via soldering. The maximum diameter of the cable - 7.3 mm.
 
Furutech FP-126(R)
High Performance Audio RCA Connectors

Rating
(PCOCC central pin)- Rhodium plated

Features
α (Alpha) OCC Conductor center pin
Copper alloy body and fluoropolymer insulation
Connections: Soldered
Specifications:
Specified for cable diameters up to 7.3mm
Dimensions: 12.6mm ± 0.1 diameter x 39.3mm overall length