Correct Opening Mechanical - Killzone, Rage, G5 Havok, Spitfire DoubleCross, etc. The primary blades are fully deployed upon entry. Over The Top Mechanical - Spitfire, Grim Reaper, etc. The blades do not fully deploy until they are inside the animal. Standard Fixed Blade - Muzzy (original), Thunderhead, G5 Montec, HellRazor etc. A standard size "classic" type of fixed blade head. Micro Fixed Blade - Slick Trick, Ramcat, Exodus, Muzzy Trocar etc. The smaller generation of fixed blade heads that have shorter ferrules and steeper blade angles.