whats the name of the part?

fagor lfu-651t dishwasher

parts required - plastic strips 12cm long with tiny rollers along the length - they fit together inside the telescopic arms inside the dishwasher that allow the top shelf to slide in and out...

all have perished & consequently the top shelf especially when full, doesn't slide in or out.
Been in touch with fagor - no joy - I have to call out an engineer to identify the part before I can order a set of new ones
Last chance to solve problem before I ditch the m,achine & buy a new one - NOT FAGOR !!!