High density teflon is manufactured to the same Mil. Spec T-27730A -- the codes that cover heat, combustionability and
This tape is made from the same resins as medium density, but less air is blown into the sheets. The end result is a High Density Teflon Tape that better protects the threads in high quality systems. It is important to note when considering this version of Teflon Tape that while it is denser, it is not thicker.