Thanks for the info.The only references I found to G5 fibres was here
The BALI tips it's hat to the Ever Ready Gillette style brushes of the 30's 40's and 50's. The 24mm knot gives compliments the 51mm tall handle perfectly. Comes with tube box as pictured.www.thewetshavingco.com
But now they have changed the ad to G4 so it looks like I was misinformed.
Nevertheless I like the brush and knot very much Alin.
Edit: they have Oumo G5 knots available
It seems I guessed right: Bali, Everest, Atlantis and Robin have the same knot (G4 fiber). I had some G4 brushes and I didn't know!
Yaqi China does not give this information about synthetic fibers used in brushes!