I am lucky enough to own 2 Kent butterscotch brushes in original condition: a V6 and a V10. It is difficult to date these, however, the closest I have come up with is 1960, going on some research that I conducted. Some say 1970s, but my money is on the earlier decade. As you can see, they each have the same "Vase" handle (hence "V"). Both have lost their decals (but I'm woking on that).
The
V6 has the following measurements:
Knot: 23mm
Loft: 46mm
Handle height:51mm
Total height: 97mm
Diameter of Base: 33mm
The handle isn't stamped, but my research shows it to be "Pure Badger".
The
V10 has the following measurements:
Knot: 26mm
Loft: 58mm
Handle height: 54mm
Total height: 112mm
Diameter of base: 37mm
The handle is stamped "Pure Badger".
As you can see, the lofts are very distinct, and the V10 has slightly finer tips. My speculation is that the longer the loft, the different the hair requirements, unless in different periods the hair was sourced from different places. My research, however, indicates that the larger the Kent V-series brush, the whiter the tips. The V10 pictured here has a loft/knot ratio of 2.23:1, while the V6 has a ratio of 2:1. That difference means the smaller brush is ever so slightly scrubbier, which is nice when that's what you want. The larger brush is wonderful for bowl/cream lathering, but I can't imagine ever wanting to use an even larger brush: the loft on this one is pretty damn BIG. The smaller one is good for face lathering, using hard soaps or 'croap'.
I realise that going by the handle they don't look that distinct, size-wise, but the camera is distorting things a little. The lofts look very different, as you can see.
Picture: