This is a scale to accompany my adjustment lever (http://www.thingiverse.com/thing:753360) It's designed to fit on a home built 480mm diameter 'speed disc' which brings the drag factor down in line with the newer models. The drag factor of my Model B ergo can now easily be adjusted from 95 to 220 without leaving the seat.
(Leave a comment if you have an ergo and this is gibberish to you and I'll happily elucidate.)