Many strobes have consistently high, or spikes in sync-line voltage, which can damage your camera's internal circuitry.
This is a voltage protected sync cord that reduces the line voltage from the strobe power pack, or monolight before it reaches your camera.
Older Hasselblad "C" Series lenses (silver) had their PC flash terminals in an awkward position on the lens barrel. This 5' coiled Household to PC sync cord has an extra long shank on the PC end, to clear the lens barrel.