WC-51 Question ...

[Valley Rock]

I scored this old 1942 WC-51 and got it fired up and drove it around after it had sat for many a moon in an old barn .

My question is, what is this box within the battery compartment that has two battery cables coming out ?
Maybe some type of surge protector for if it had radios ?

I'm sure I'll have more questions, like does anyone have any good or nos spare u-joints for it ?


Thanks .