The Da Vinci Maestro travel pocket brushes are what I use besides the Holbein waterbrush.
I bought four of these in various sizes, 2, 4, 6 and 8. The one I use often is size 6. Size 8 is a huge step up from 6, which explains why it cost almost twice as much.
These are the 1503 series of travel brushes. Do not confuse these with the 1573 series which are made of synthetic hair marketed as Cosmotop Spin.
They are made from Winter Siberian Kolinsky Red Sable hair. That's top quality hair. The hair is extremely durable. I've used them for around 9 months and they don't show any signs of wearing out. Just for comparison, during the same time, I've worn out three waterbrushes with synthetic tips.
The cap protects the brush tips while you're traveling. At the top of the cap is a tiny hole for ventilation. However, the hole is too small to dry the brush fully so you need to dry it out a bit first before putting the cap on.
The black plastic is really hard and well made.
The sable brush is able to create a total even flat wash effortlessly. That's the reason to go for a traditional brush. The waterbrush wash by comparison is patchy and you need really fine technique to get an even flat wash.
Below's a sketch where I used the sable brush.
This is the line work on a 12 by 9 inch Cotman watercolour paper.
The first wash was made with a size 6 brush and Graphitone
Sable brushes are not cheap. However, they are still amazing value for the money simply because of the durable high quality brush hair. They can last a long time with proper care like simple cleaning with water.
Highly recommended to all who uses watercolour.