The following is provided by Shavemac:
Silvertip D01 2-Band
Silver tip D01 2-band has the highest strength and density. The brush form remains very compact and dimensionally stable, but is not quite as soft.
2-Band Badger Hair
The 2-band shaving brush features silver shimmering tips and a long dark section down to the handle, unlike the more commonly seen 3-band hair with its light-dark-light sections. This unique effect is achieved through the use of specially long badger hair, known for their appropriate long sections, density, and firmness. Due to the trimming of the badger hair to its final length, more weight is needed, resulting in a higher cost. Additionally, these long hair are rare and may not always be available. The brush is available in both Silvertip 2-Band and Silvertip D01 2-Band options.