Where to buy EM7355 for CF20?

So a while ago I have bought 3 CF20s without 4G cards in them. Now I am looking to add the 4g capabilities to the toughbooks. I was searching around and either EM7355 or EM7455 work.
But I am mostly able to find Dell, HP or Lenovo cards and they will not work with the panasonic CF20 without flashing them.
Any help is appreciated.

Thank you.

I’d suggest you to contact Panasonic as only the OEM can ensure the compatibility of HW/BIOS/SW package, etc. with the platform.