We stumbled onto a website that promises to help you make a device which can prevent alien abductions. It's called the thought screen helmet and the inventor claims it has helped former abductees prevent further abductions for over 20 years.
The website is a how to guide so you can make your own helmet. It works by stimulating brain activity and preventing alien telepathy from penetrating one's mind. Though the aliens have tried to figure out how the technology works, they have not been successful.
The helmet is made specifically from a material called Velostat. Eight sheets of the material, part number 1706, are used to line a ball cap or similar. Total cost to make a thought screen helmet is $45.
Were a bit dubious as the inventor says that he has worked with patients who have neurological problems for 16 years. The inventor does admit to having one helmet fail. No word on what happened to that abductee.