AEDIKO 4pcs Relay Module DC 12V Relay Board 1 Channel with Optocoupler Isolation Support High or Low Level Trigger

Good quality, you can choose high and low trigger voltage.Terminals could be a bit bigger.Well-packed, individually in antistatic bags.

Works as expected, though, like for a lot of other modules coming from China, claiming optocoupler isolation is pure nonsense in the way it is designed. To have an isolated module, there shall be two completely separated connections points, at the LED side of the optocoupler, with no common ground to the supply. Other than this, the device can be designed very well without an optocoupler, being as "isolated" without the optocoupler, as it is with the optocoupler. This module is, of course, non isolated, but it does the job I need it for.

Works exactly as expected. Triggered on a rising 24V from a rain sensor. Easy to use and install.

I guess you get what you pay for but only 3 of my relay modules functioned. The fourth relay refuses to activate and just gets hot.

I used this relay to drive a pond pump (240v) via a float switch (reed) driven by a 12 v supply… to control water level in a pondWorks well

Bought the board to add to an arduino nano GRBL board for my CNC plasma machine… it works what more could you ask for..

The terminal blocks have a weird flap on and is can be really difficult to get even a thin wire in. Not sure why they couldn't just make them normal plain screws.That said, they work fine and have choice of NC/NO like every other relay in the world. I was activating these 5v relays using 5v from an arduino or using 3xAAA batteries. No problems either way. Bought from amazon as I needed them the next day and couldn't wait 38 days to get them delivered from you know who.

These relays work well with both high and low level inputs.One thing that lets them down is the quality of the screw terminal blocks - I have seen better.