Sometimes I find the extractor blades in the NutriBullet Pro 900 too tight to remove by hand. I wanted something I could mount under a cabinet to help loosen (or tighten) the extractor blades. Using two hands to turn the blender cup gives plenty of leverage and should work for people with limited hand strength.

I found a different model to which I made a few quick-and-dirty modifications within PrusaSlicer by adding parts and negative volumes. Aside from removing the handgrip part of original model, the most significant change was removing 3mm from the inside of the key to accommodate the extra "foot" feature on the inside of the teeth (see picture with orange circle). A picture from the original author shows their version of extractor blades did not include this extra feature.

The attached 3mf version includes the additional parts, negative volumes, and modifiers to strengthen the "teeth" and screw holes.