The Cádo Motus adapter allows you to mount any long-mount inline boot onto a clap ice blade without compromising the for/aft position of the boot on the blade.
Typical mount spacing for inline boots is 195mm and does not match with the shorter mounting for clap ice blades. Inline boots have the front mounting point to much forward, right under the toes, whereas ice speedskating boots have their front mount about 35mm backward at the metatarsals (probably a more efficient position in terms of biomechanics). The mount positions of ice boots depends per boot size, they go up/down 5mm for every size and run from 140mm up to 200mm. The lever of the clap blade onto which the boot is mounted is available in different lengths to match with the boot sizes. Marchese offers 4 different lengths: 150, 165, 180 and 195mm.
A common mistake is that skaters think they can use a blade with 195mm bridge, but an inline boot would be too much at the back of the skate making it pretty nervous to skate on. A centered position is absolutely required in order to be able to lengthen your push off, slow down your stoke frequency, and start skating as an ice skater!
The additional height of the adapter is often not a problem since inline skaters are used to be higher. The heel platform of a typical inline frame is about 105-110mm above the ground where an ice blade just measures 65mm.
The illustration below shows the problem of the different mount positions between an inline setup and a clap ice blade (you notice also why mount separation changed from 165 to 195mm for inlines when '4 big wheels' became the standard).