Scissor Blades

Information
The Scissor Blade, as explained by Satsuki, is a special weapon that was developed specifically to combat Goku Uniforms, and as such, can cut them. It resembles a giant half scissor.

There are still things unknown about these blades and who made them.

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