A new article by New York City-based architecture blog Zephyr explains the process behind a double insulated mug, which we all know looks like a double tube of duct tape.

If you’ve never done it, then read on to see how to build this amazing mug.

The double insulated foam insulation comes in a few sizes, from two to five inches in diameter.

The first size is usually about the size of a thumb, and the next size is a little smaller than that.

The foam is covered with duct tapers, and when the mug is assembled, the duct tape is stretched in front of the mug to create a double seal.

When the duct taper is pushed against the foam, it releases the duct taped foam.

The duct tape can be removed later, but it’s not needed, Zephry says.

This article originally appeared on Zephyrs blog, and was reprinted with permission.