Having used Rapidograph technical drawing pens forever, I finally switched to the disposable little Sakura’s Pigma Micron pen and love it. Bob Mankoff, cartoon editor of the New Yorker, draws all his pointillistic funnies with one. It costs a mere $2.98, as opposed to $25+ for a Rapidograph. Micron pens come in an array of point/line widths: #005 (0.20mm), #01 (0.25mm), #02 (0.30mm), #03 (0.35mm), #05 (0.45mm), #08 (0.50mm) points.

If you have never tried a Micron pen, you can buy a 6-Piece Sampler Pen Set in Black so you can test the point size(s) that suit you best.
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Sally says she can’t write with anything else. She says her writing looks “cooler”, and it feels great in her hand. Her favorite is the 01/0.25-mm Micron in black.