The relay boards are marked "2 Relay Module" "2PH63091A" .
   Each relay has 3 screws labeled "NO" "COM" "NC" and 4 header pins. The
   header pins are labelled "JD-VCC" "VCC" "GND" / "GND" "IN1" "IN2" "VCC"
   . One of the boards has a removable jumper bridging JD-VCC and VCC.