Review on KEYESTUDIO 4 Channel Relay Shield 5V: Arduino R3, ARM, PIC, AVR, STM32, Raspberry Pi Expansion Board by Chad Boho

These features are as advertised. They are attached to pins 4-7 and are not isolated relays. Meets the needs of the application I used it in, great overall! I only have bad things to say about them: Do not route SDA/SCL signals on R3. There are no jumpers to configure which inputs control which relays, it would be nice to have at least one alternative for each, but the rest of the project could be designed around it. it uses the same pins, hence the second problem. If you need to add a relay to a quick project this is what you need, reliable after a month of fairly heavy use on both motors and LED lighting loads.