It's 30mm I am beginning to wonder if it may be too large, I guess I will see when it gets here.
Yaqi synthetics are good though I really like mine. The next brush will be 7 and I guess that will have to do as I am running short of room.
24mm is the biggest I currently have. I had a 26mm Razorock Big Bruce, briefly but changed it for the 24mm Bruce. The 26mm one felt like I was wiping a mop across my face. Anything bigger seems like total overkill to me.