This probably works well, but I needed the item on the right, not left. I was thinking this would allow my controller to add zones beyond three to each module but no luck. I did order the other 3-Zone module from the same folks and it arrived promptly and worked fine, so I would expect this would work fine if it's appropriate for you.Take a look for the tab on the left (pictured). It wouldn't let this slide into mine which is why I had issues.