$15 for all 4 pcb's-- free shipping (in a thick envelope). [SOLD]
These are hard to get anymore since I can't remember when the last wireless COOP was.
Typically you can install these on a Lynx Express and enable it to recieve wireless DMX,
assuming you have at least one Lynx Tx within range (I've never had one too far).
These are the PCB(s) only ... you would have to order the parts from the wiki mouser link
for ex/rx.
PM if interested