BHT-1 or BHT-2 Baler Mounted Hay Moisture Tester

I am looking at getting a Agra Tronix BHT-1 or BHT-2 baler mounted hay moisture tester. I am planning on installing it in my small square baler. What is the difference between the two moisture testers . I was reading the BHT-2 has 2 sensor cables and the BHT-1 has only 1.Is there any other brand that I may want to look at.  Thanks for the information 

BHT-1 or BHT-2 Baler Mounted Hay Moisture Tester