This is an X-Acto blade holder modeled after the Fiskars fingertip craft knife holder. It allows you to push directly down on the rear of the blade, & gives you a great deal of control over where it goes.
It doesn't really do pushing/stabbing type motions, because THAT'S NOT HOW YOU'RE SUPPOSED TO USE X-ACTO BLADES, CHARLES.
You'll want to have some way to push the blade securely under the snap - I push the tip against the cutting mat, which seems to do the trick.
Blue - I'd recommend something bright, so you can find it.
You'll need some needlenose to get the supports out from under the snap...or another X-Acto blade. Although that does seem to defeat the purpose...