I decided to try the da Vinci series 1573 travel brushes after being impressed by the series 1503 Maestro watercolour travel brushes which I have been using for years.
The 1573 series are marketed as Cosmotop Spin while the series 1503 are known as the Maestro.
Cosmotop Spin uses synthetic hair while the Maestro uses Winter Siberian Kolinsky red sable hair.
In the picture above, 1573 is on the left. You can see that after years of use on the Maestro, that brush still maintains a sharp tip. I wonder if the synthetic can last that long.
The brush body is made of black hard plastic, while the part holding the hair is made of metal. It's a portable design where you can collapse the brush, and the cap will protect the brush tips. At the cap's tip, there's a small hole for ventilation.
They 1573 series are available from sizes 1 to 12. I typically use either size 4 or 6 for sketchbook sizes of A5 to A4.
The synthetic brush tip is firm, has a nice springy feel to it, and can maintain a sharp tip. It can also hold a lot of water.
The downside is, synthetic brush hair is not as flexible as sable brush hair. With sable hair, you can remove most of the water when you flick the brush in a snapping movement. You know like how some animals would shake off water from their hairy bodies? When you can shake the water off easily, you can use the dried point to collect extra pools of water on your watercolour paper, or to mix new colours. I tried flicking the synthetic brush and it is not easy to get rid of the water.
Sometimes I would use a water loaded sable brush to transfer some water to the mixing pan. When I tap the sable brush tip to the surface, a good amount of water will come out. When I do the same thing with the synthetic brush, not a lot of water comes out that way. So while the synthetic brush does hold a lot of water, it's not easy to get the water out for purposes I've just mentioned.
As for painting, well, it's a terrific brush, and is comparable to sable brush. It can do washes or details depending on your brush size.
If you're just starting out, or learning watercolour, or don't mind synthetic brushes, it's fine to get the da Vinci series 1573 Cosmotop Spin watercolour brushes. They are good compact travel brushes.
Personally, I would recommend the Maestro over Cosmotop Spin. The 1503 series Maestro watercolour brushes might be more expensive, but they are just better.
Before you buy, do compare the prices between the Cosmotop Spin with other sable brushes. If the price difference is not too much, I recommend going for the latter. Because sometimes, da Vinci can price themselves too high.