Review on ARCELI KY 019 Channel Module Arduino by David Naranjo

They definitely work but only for a few uses. I burned 2 of these in 10 days. Like some other reviewers, I use them to switch my 3D printer to 24V. I'm running some tests to see if I'm trying to break too much load. They seem to work when the printer is fully cool and most of the fans are already off, but I know that at least the second one didn't turn on when the printer was cool (I've never switched while printing or under heavy load). They may work better in very low power applications so I don't think they are a 1 star product, they just should be clearer about that, what they can handle. being able to swap them out if 1 breaks so they seem like a decent deal for the price. Now I just have to find some that can switch with higher current!