Hey Ed, ITW Linx (the people that now make the Panamax line) make a 66 block protector specifically for the Panasonic Digital system. It clamps at 100V. You could use it as secondary protection.

You know I'm not a Panasonic guy, buy I have used some of these, at different voltages, with good success.

Here is a link https://www.itwlinx.com/products/subcategory.asp?category=41&subcategory=4