Xin Bowen Brushes
Despite the collection name, most of what is stocked here is the White Pearl and Keep Smiling ranges rather than Xin Bowen branded pieces: White Pearl covers Round No. 7 and No. 9, Flat sizes from No. 2 up to No. 14, Filbert No. 4 and No. 11, a Dagger No. 8, a Fan Brush no. 5, an Angle Flat No. 10 and a Liner Script No. 1, while Keep Smiling supplies Flat brushes numbered 1 through 8.
A full flat and round numbering run
Because two brands' numbering sits side by side here, sizes are not always directly comparable between a White Pearl Flat No. 6 and a Keep Smiling Flat No. 6. Check the bristle length in the product photo if an exact size matters, rather than assuming the numbers line up between brands.
The two brushes actually labelled Xin Bowen, the Filbert Brush No. 2 and Round Brush no. 12, sit in the same families as the filbert brushes and flat brushes pages if you want to compare sizing against other brands.