Review on Relay Module with Optocoupler Isolation Trigger: Enhanced Performance and Safety by Dennis Goozmer

Not what was sent in the photo. First, with dimensions of 52mm x 77mm, it is too large. The photos show 40mm x 67mm. This alone means that it is not suitable for the required application. Second, without instructions or the ability to read Chinese characters, I have no idea what a switch, potentiometer, or "set" knob is for. It might be a decent component but I have no idea and can't use it.