No, you were correct in your first post, it is a photo resistor. We call it an LDR, which is a light dependent resistor. We actually sort these components through a proprietary sorting process, so the pair is matched with each other. So you’ll probably need to get a new pair from us. You can try to use pre-manufactured optocouplers, but I can’t guarantee the results. You’ll want to find optocouplers that get under 10k (under 5k is better) in the light and over 5M in the dark. The should respond relatively quickly too, within 1 second they should reach these values. If you can find some optocouplers that respond in this way, that will probably work. But feel free to experiment too…pretty much any optocouplers will work, but how well they work just depends how close they are to the proper specs. Email us if you want to order some new LDRs from us.