2Ch wireless receiver options for Panasonic Cameras

I'm looking for a slot-in style 2-channel wireless receiver that will fit Panasonic ENG cameras. I'm having a hard time finding any that are not configured for Sony systems. I don't want to pay $700+ for a Lectrosonics, Just need something less than $300 if possible. Feq range, new or used doesn't matter.

Can anyone point me to a good source, brand or model?