Review on 🕓 KNACRO PTR4-SP Controller 6-40V 4-Channel Programmable Time Relay Delay Switch Module 99 Groups Time - for DC 6V, 9V, 12V, 24V, 36V and Beyond by Joel Norfork

controller works as advertised and has been reliable so far. The main disadvantage is the instructions, which are difficult to interpret. But thanks to the fact that the device was on while I read and tried something, I was able to figure everything out without too much trouble. My application as a controller for aquarium lighting. I connected the controller to 4 LED arrays to activate different light intensities (and colors) at different times of the day. For example, sometimes blue is just like moonlight, sometimes reddish and faint at dusk, sometimes all the lights are on like bright daylight, sometimes everything is off for a dark night, and so on. Overall recommended, especially considering the price. EDIT: After a few weeks, I found that the timings were incorrect. By my standards, it's 0.51% faster, meaning each 24-hour cycle ends 7 minutes 20 seconds earlier than the previous one. One hour is lost every 8 days. I think that's pretty bad for a digital timer. I fixed this by padding my program with an extra 7 minutes in each 24 hour cycle and now the system intelligently keeps track of the true 24 hour cycle time. I can still recommend if the buyer 1) expects poor instructions and 2) needs to increase the time if accuracy is important to your application. I'm sticking with 4 stars and approaching the limit of 3.