This is an ARRI Head-to-Ballast Cable. The 50' (15.2 m) long cable is compatible with ARRISUN 5, 12 Plus, 18, and 40/25 heads. It's also compatible with the ARRIMAX M18, the ARRI X X5 and X12, D5 and D12 Fresnels and the Compact 575 and 1200 heads.