Scissor Blades

Information
Scissor Blades, as explained by Satsuki Kiryuin, are special weapons that were developed specifically to combat Goku Uniforms, and as such, can cut them. They resemble a giant half scissor.

Many facts about these weapons are unknown, such as whether there is only one pair and where they come from.

Red Scissor Blade
Ryūko Matoi owns a red Scissor Blade, which was used to kill her father, Isshin Matoi. It can expand into a longer sword (known as Decapitation Mode) or collapse into a normally-sized scissor half.

Purple Scissor Blade
Nui Harime owns a purple Scissor Blade with a circular handle, which she claims is the other half of Ryūko's own blade. It is as of yet unknown if it can also change size or form, though it is likely.