That looks like an MOV, a Metal Oxide Varistor. It is a transient suppressor rated to be connected directly across the AC powerline. It is made by Panasonic (Mitsubishi).

If all of that is correct, the rated operating voltage is 270 V. That is for a 240 Vac mains plus some margin.

That looks like an MOV, a Metal Oxide Varistor. It is a transient suppressor rated to be connected directly across the AC powerline. It is made by Panasonic (Mitsubishi).

If all of that is correct, the rated operating voltage is 270 Vdc, or 175 Vacrms.