VPI Brushes

I'm wondering what the difference(s) is (are) between the VPI 16.5 record cleaning brush and the VPI 17 brush -- other than the $15+ difference in price. I have a 16.5 but no access to the 17; hence my question.

Many thanks for your help.
if that' the applicator brush...maybe it's the fact the the 17 has a tube in the brush for the semi auto fluid applications...