Its Abba Rail by the look of it.
If it is its the rail would be BR25R-L1000-N and the bearing would be the BRH25A.
We sell the bearings for £42 and the rail would be £80.00
This is new and there is also VAt to include.
Second hand would be about 25% of this, but you really need two bearings per rail and would normally have two rails.