I would also be very interested in this. On the manufacturer's website (https://www.einhell.ch/werkzeug...) you won't find anything with the designation "RT-RO 55". What else I could imagine would be something along the lines of TE-RO 1255 + compass, rip fence and copying sleeve = RT-RO 55. I will hopefully be able to report more precisely as soon as I have picked up my machine :)

TE-RO 1255 is the "expert unit" - so presumably better bearings, more reliable parts, etc. . .