Better Splay & Less Springiness: The traditional bulb shape with shorter hairs around the edges allows for easier play and less springiness compared to the "S" series brushes.
Synthetic Alternative to Boar: If you're looking for a synthetic alternative to boar this is the closest you're going to get. The water retention, splay, backbone all lends itself to similar characteristics to boar. Since it's synthetic it'll never be quite the same of course, but for a synthetic, it's the closest I've tried to boar.
Base Diameter: 28mm (± 0.5 - 1mm)
Love this knot!
For the money, you can’t go wrong. This knot lathers quickly, with a 50mm loft, this knot will whip soap into lather faster than all my knots. It does shed, I’ll have to keep an eye on that, but this knot is the best bang for the buck performance-wise, IMO