I've got eight X-10 Universal modules for sale. Seven are PUM01and one is a UM506. They're basically the same. They let you control relays or other low-voltage loads from X-10. I used them to switch electric valves for my lawn watering. It worked great, but I replaced it with a "normal" sprinkler timer so that my gardener could program it.
Asking $10 each plus actual shipping from Irvine, CA. If you are local, you can pick them up. If you buy five or more, and are interested in using them for irrigation, I'll throw in the transformer I've been using. I can take PayPal or money orders/cashiers checks. I've got a perfect eBay feedback of 235plus lots of other Internet deals going back about 20 years.
Let me know if you have any questions!