But basically these are  curved and double-curved I I believe that the tech department , in their um  in their  message to me , that they were referring to the number of th curves in the bottom. I have no idea exactly what they're talking about ,
Okay.
but that's what they told me ,  uncurved , flat , curved , or double-curved.
I would guess this like this pen would be kinda like a double-curved , where it's curved on m m multiple axes , right ? I think curved means just curved in one axis and double-curved is curved in two axes