Kolinsky sable round brush size 12One Stroke (3/4”) flatPrice between $25-40Not a travel size, but excellent quality for the price
Round size 6 and flat size 8. I bought it years ago and still in great shape. Can hold a lot of water, price between 14-30 € each, these are my favorites for travel.
Round #4 synthetic fibers but it holds twice as much water as conventional brushes. Very inexpensive, around US$10