It's a funny looking little bass with its elongated body and short neck. Unlike the later 5-strings that emerged from various manufacturers from the late 80s onwards, the extra string isn't a low B, it's a high C. The Bass VI didn't actually offer an extended range to that offered by Fender's existing Precision and Jazz Basses, it simply offered an alternative way of playing, possibly more suited to those of a smaller stature who might find those other Fender Basses more unwieldy. Instead of playing up and down the neck as much, you could play across it instead.
The auction for this one ends later tonight. It's going to go for a few thousand dollars, that's for certain. These basses weren't a resounding success sales-wise and as such this is a very rare Fender.
Edit: Sold for $3,795.