Dremel 105 ball engraving cutter
Dremel 105 has a small ball working head and a 1/8-inch shank in the documented model family.

How to choose
Compare the working ball with a wider point if you want a small contact area. Confirm both the maker’s material guidance and the holder size.
Compatibility and limits
Small ball engraving head · 1/8-inch shank in the documented family
Care
Before mounting the accessory, check its speed rating against the tool and use the holder specified for its shank or mandrel. Refer to the exact model instructions for the workpiece.
Questions before buying
What if the 105 touches too little of the surface for the mark I need?
Compare the larger ball of the 106. Both give a rounded contact, so working-head size helps you choose without assuming a different tool holder.