In international freight transportation, bubble goods refer to goods that are relatively large in size but relatively light in weight, occupying more transportation space. This cargo is divided according to its weight-to-volume ratio, usually measured using a value called "density" or "size factor". The specific division criteria may vary depending on the carrier or country, but the following are common divisions in general:

1. Bubble goods (throwing goods): goods that are light in size and have a density lower than a certain standard are called bubble goods. These goods take up more space during transportation, but are relatively light in weight. For example, air-filled plastic balloons or styrofoam products, foam boxes, styrofoam packaging materials, foam sheets or granules, soft toys, etc.

2. Physical goods (heavy goods): For goods whose density is higher than a certain standard, they are considered as physical goods. These goods are relatively heavy in weight and take up less space. For example, metal products or stone materials, iron blocks, aluminum plates, marble products, granite products, auto parts, engines, transmissions, chassis parts, etc.

The specific division criteria may vary with different shipping companies or countries. For some special types of goods, there may be special regulations to determine whether they are bubble goods or real goods. Correspondingly, the billing method of the foam-to-weight ratio of different goods in different countries will also be different. For example, the overweight cargo of our Iman-China-Saudi International Line is calculated according to the ratio of 1CBM: 400kg, and the overweight cargo of the China-Pakistan International Line is calculated according to the ratio of 1CBM: 300kg. Therefore, before transportation, it is necessary to do a good job of verification with the cooperative freight forwarding company or international transportation company.