Interlock knit
Technique
Fabric construction for the black t-shirt to achieve greater structure, smoothness, and durability
"For our t-shirt, what I chose to use is what's called an interlock knit. An interlock knit is essentially a double-faced single jersey knit. It has the same loops on the front as it does on the back. The result of that is a fabric that is more structured, s..."
More source quotes
"If you want the top tier stability, look for a interlock knit. Think of it as a double-sided jersey."