Kydex guru PHLster makes a sheath for the Ka-Bar TDI that is very popular. Demand for the sheath has outpaced his ability to produce them since their introduction. PHLster has been working to streamline production of the sheath in an effort to increase the rate at which they can be created. The good news is that they have succeeded.
The original sheath was foam pressed and had a curved shape to it that made it hand specific. The new version is now vacuum formed and has a flat shape that makes it ambidextrous and more user configurable. the result of these changes is a sheath that has the same level of quality but can be produced more easily. Many users are also reporting that the new flat shape is actually more comfortable too.
Check out PHLster Fightworthy TDI Sheath.