The AV Battery Monitor BMID is installed on the battery and has two parts:
• An electrolyte emersed thermistor that constantly monitors battery temperature which in turn signals the charger to adjust its algorithm for a safe charge, and
• An advanced electronic device that stores the identity and proper charging profile for a battery as well as documenting and storing charging event information including dates and times, begin and end voltages and currents, and cumulative amp hours in the battery.  These units allow for fast charging of your 36-48V battery without overheating and destroying the battery cells.
The Buy it Now selling price is for all three units. 
Picture number 3 is only to show what the unit looks like, it is not for sale, it is an old used unit.
These New BMIDs are used on Forklifts, Golf carts, and in airport GSE Electric tugs.  
The electrolyte thermistor is not included, this sale is only for the BMIDs. 
The price for one of the BMIDs is around $395.00 each. 
I am selling all three for $150,00 .