The eraser's B rating (e.g., 2b and 4b) usually indicates the eraser's softness and erasing ability. According to the search results, the main difference between 2b and 4b erasers is their erasing ability and softness.
1.Erasing ability: The erasing ability of a 4B eraser is usually stronger than that of a 2B eraser. A 4b eraser can erase 4 units of graphite traces, while a 2b eraser can erase 2 units of graphite traces. This means that the 4b eraser is more effective at erasing heavier pencil marks.
2.Hardness: The 4B eraser is softer than the 2B eraser, which makes it softer when erasing and less likely to scratch the paper. The 2b eraser, on the other hand, is relatively stiff and may require more force when erasing.
3.Accuracy: A 2b eraser may be more accurate than a 4b eraser when erasing because it is moderately hard and not easy to erase parts that shouldn't be erased.
Which eraser to use better depends on the individual's needs and use case. If you need to erase heavier pencil marks, or need a softer eraser in your drawings for a soft effect, a 4b eraser may be more suitable for you. And if you need to do a precise erase while writing or taking notes, or are worried that the eraser will erase the paper, then a 2b eraser may be a better choice.
In a regular exam, the 2b eraser is sometimes recommended because its precision may be more suitable for the meticulous work in the exam. However, this does not mean that the 4b eraser is bad, and it may be more practical in other contexts, such as art creation. Overall, the choice of eraser should be decided based on personal preference and actual needs.