This design has a small cup-hole that enables the tool to sit straight no matter if you prefer to insert it upside down or right side up as shown in the pictures.
Other designs have a refill blade storage section but I find that unnecessary since this design can hold the refills inside (by opening the black tip).
Might update it with a 45 deg support under the stands, for added rigidity, but it's working fine for me.
The pictures show the hole-less version, but one with screw holes is available in the files.
This file can be printed laying on its back for quicker, support-less printing, but do note that the holes will be prone to breakage if you pull out the tool improperly, it happened to me once.
The author marked this model as their own original creation.