FRC 4607 does have a couple of
Dual Pro SR3 chargers from AndyMark. They are great and we have had no problems with them charging our batteries...
BUT,
if I could go back and redo our purchase, I would go for the
Battery Tender as it offers more charging stations and is more compact than our two Dual Pro SR3's. When space is a commodity in a PIT, every inch counts.
Just my two cents.