If you live in the USA, you may have noticed that some products' shipping fees vary a lot from model to model, and day to day. This is due to their availability in our warehouse in the USA. If a model is available at the time of your purchase in our USA warehouse, you will be able to get it shipped with USPS at competitive prices. However, if it is not available in our warehouse at that time, but in stock in another country, it will be shipped with more expensive international carriers such as DHL.

Example:

These Superglide Feet were only stocked at HQ in South Korea at this time:

This Mousepad was stocked in the USA warehouse at this time: