Hi,
Thank you for your interest in our product. We have tested our sensor with 100m cable. It worked OK but readings show from 0.3V to 1.35V. For 25m cable, we have had readings 0.15V to 1.15V. For now, we don't plan for a sensor with longer cable but you can easily extend it. Currently, we run Indiegogo campaign and we will have to deliver sensors to our backers first. Probably at the end of November, we will start selling on other platforms with Paypal payment option.