V-42 stiletto

The V-42 is an American fighting knife first issued in 1942 to the First Special Service Force, the joint American Canadian commando unit known as the Devil's Brigade. Based on the Fairbairn-Sykes design, it used a distinctive double hollow ground blade meant for penetration, reportedly able to punch through a steel helmet and its liner with a single thrust, and a thumb groove on the ricasso helped the user hold the blade flat for both slashing and stabbing. W. R. Case and Sons Cutlery Company manufactured about 3,000 of the knives during the war, and only members of the unit's combat echelon received their own issued blade.