I use this product in a common 9 vdc battery and it was fine.I use it then in a car some alarms and senders.It was fine too.Then I connect it to a Diesel CAN Bus(J1939) High and and the black wire to Batt(-).Of course the was no a voltage signal but the device blink show me that the CAN was working fine.So guys what do you want better than this for the price?.5 stars.CAN signal frequency is so high than 5 KHz.And I test this for more than 25 min.