Haase had made a very interesting new hub that could be defined as "multiuse". It's composed of three elements, a steel pin with grooves for two keys and lines for checking front width, wheel holder hub and disc holder hub. The latter are splined separately on the steel pin, each has its own key and a grub screw is used to lock them.
Therefore the wheel hub is independent from the brake disc and this makes it easier to get perfect centring of disc respect to calliper, avoiding any abnormal pad wear. Another advantage is that the disc holder hub can be removed and left "at home" enabling driver to pass from a 125 set uo to a 100 without having to do without the fine solution of having a front hub instead of the usual pin with rim and bearing. You can also use a front flange disc bearer on the axle for fixing front disc (same keys), this is cheaper all round. With just one type of hub (same front hub can be mounted either on the right or left) you can connect 3 disc.
These can be self-ventilated or normal. As far as measurements are concerned, the internal diameter of the 40 mm Ø hubs (or external pin diameter) it gives you the opportunity of mounting them on same size axles.
However, hubs are available in different sizes too, from 25, 30 and 50 mm for other classes and different types of axles.
All hubs are made of top quality aluminium alloy with important mechanical characteristics.