This is a small sized X-Acto knife blade box cutter. You will need a RESIN printer as normal FDM 3d printers simply can not create this level of detail. Also, print more than you need. I printed a set of 8 and only had enough parts print properly to create 3 blades. You'll also need a single small sized X-Acto blade, and M2x4 Bolt and Nut.

This uses a compliant mechanism to lock the blade in place, you should feel and hear a nice pop sound when extending or retracting the blade.