This is a car-specific plug & play adapter cable.
Quadlock 3 connection.
Length: approx. 1.5 m.
Compatible with these vehicles:
Audi: A3 + Q3
Skoda: Octavia
VW: Golf 7
Also compatible with these Axton DSP amplifiers: A430DSP, A480DSP, A500DSP/A530DSP/A580DSP and A540DSP/A590DSP.
Axton article number: N-A480DSP-ISO33.