In close-quarters fighting there is no more deadly weapon than the knife. In choosing a knife there are two important factors to bear in mind: balance and keenness. The hilt should fit easily in your hand, and the blade should not be so heavy that it tends to drag the hilt from your fingers in a loose grip. It is essential that the blade have a sharp stabbing point and good cutting edges, because an artery torn through (as against a clean cut) tends to contract and stop the bleeding. If a main artery is cleanly severed, the wounded man will quickly lose consciousness and die have a look here http://en.wikipedia...._Fighting_Knife
have a look here for the best description of the British FS fighting knife http://www.gotavapen.se/gota/artiklar/fs/fs_knife1.htm
and here for the original sheath designs
http://www.gotavapen.se/gota/artiklar/fs/more/fs_sheaths_english.htm