Overall good design and works well. In my opinion good value for money. As others have pointed out, documentation is not included. With the RPI4, the pin numbers and the corresponding relay assignments are listed here. Sorry I didn't bother to write down the pin vs GPIO. 29=131=233=336=435=538=640=737=8 Works great; Currently my production server/relay is Node-RED. No questions.
Gikfun Screw Shield Expansion Board: Enhance Arduino UNO R3 with the EK7007 Add-On
11 Review
Vilros Raspberry Pi 4 4GB Complete Starter Kit - Black Fan-Cooled Aluminum Case for Heavy-Duty Performance
12 Review
π MCIGICM 2 Channel DC 5V Relay Module: Optocoupler Low Level Trigger Expansion Board for Arduino UNO R3, DSP, ARM, PIC, AVR, STM32, Raspberry Pi
11 Review
LAFVIN Super Starter Kit for Arduino R3 Mega2560 Mega328 Nano with Detailed Tutorial - Compatible with Arduino IDE
11 Review
Comprehensive 500pcs Laptop Screw Kit Set for π© IBM HP Dell Lenovo Samsung Sony Toshiba Gateway Acer
12 Review
36-Pack Black Rubber PC CPU/Case Fan Screws/Rivets Set for Computer
11 Review
π§ Premium Repair Replacement Screws & Tools for MacBook Pro Retina 15"/13" - Complete Bottom Case Set
10 Review
uxcell 3.5" HDD Screw Black 200pcs for Computer PC Case - Flat Phillips Head - 6#-32 - Hard Drive Fasteners
10 Review