An important criterion for identifying abalone grade is the number of heads. The so-called "head" refers to the number of abalone with uniform size in a Sima Jin (about 0.6 kg), such as 2, 3, 5, 10, 20 and so on. The smaller the quantity, the more expensive the abalone is, so there is also a saying that it is difficult to buy two abalones with money. 1, abalone with two heads is the best, which is hard to see. Among many abalones, Japanese abalone has the least number of heads, followed by Jipin, and hemp has the smallest volume and the largest number of heads.

Abalone is 4 per catty, but there are also regional differences.