A Question About Secret on Yesasia

[immel]

The only information that YesAsia gives on that subject is,

* What is a 'shipment unit'?
The shipping and handling fee we charge for each item depends on its weight, dimension and the complexity of packaging and processing it requires. For simplicity, we assign a 'shipment unit' to each item. For example, one standard CD or VCD usually counts for one shipment unit whereas a bulkier box set, toys, or posters may count for more units. The shipment unit for each item is displayed on its product page, where you can also find other product details and descriptions.

There isn't any definition for a YesAsia unit, they put what's appropriate.