3D printing pens...???

[DR]

Are they any good? I have a 3D printer my grandson likes to print on, but he's seen the pens and wants one for Christmas.

Do they use regular filament? I'd rather than buy something that uses proprietary filament.

Any thoughts on them?

[small.planes]

They are ok for ‘crafting’ but don’t expect to do precision 3D printing with them.
The one my daughter has takes 1.75mm PLA. We usually just cut some off what ever reel is handy.

Hth
Dave