Mantis Chaos II Tanto Blade 8 1/4in. MANF4CM. The Mantis MF-4 Series Knives is probably the design that is responsible for bringing Mantis to where we are today in the industry. Its angular and very industrial appearance confuses the eye. Laser cut from a single piece of stainless and finally 8 individual blocks of G-10 are screwed into the tang with 440-A stainless screws. The Mantis Chaos Fixed Blade Knife is without a doubt a true tactical tool. Specifications for Mantis Chaos Knife: Overall Length: 8 1/4" Blade Length: 3 1/2" Package Contents: Mantis Chaos Tanto Blade Mantis MANF4CM: Chaos 2 Tanto Blade 8 1/4in.