Microtech Combat Troodon Wharncliffe OTF Knife Satin Plain Sterile 2007 Automatic OTF knives. The Combat Troodon is a Dual Action OTF Auto Fire and Auto Retract that is 9.50 inches overall open length, 5.75 inches closed with a 3.80 inch blade. It is 25% larger than their flagship, the Microtech Troodon.