The X-Ray Remote Extender allowed you to control your AV gear, through walls,floors, cabinets up to 40 metres away.
The extender is no longer available, but these replacement generic batteries (to keep this extender running well) are.
How does it work?
The XRAY Remote transmitter was the same size as a AAA battery, so you just replace one of the batteries in your remote with the transmitter (or transmitter and AA sleeve), connect the receiver to your appliance and you’re all set.
The battery power from the removed battery is replaced with one of these 3/4 size AAA rechargeable batteries.
These batteries continue to be widely available, and in normal conditions last between 2 and 4 years
x-ray remote batteries
x ray remote repeater battery