Playing with my new Sharpie pens. The retractable Sharpie Pen has a smooth, easy, retracting action. It’s comparable in diameter to the Staedtler pigment liner 0.3 mm. The retractable’s black ink is lighter than the Staedtler’s, but ink flow is smoother. The retractable is also a smidge finer than the non-retractable Sharpie Fine Point Pen. Both much finer than the Sharpie Ultra Fine Point marker. Will happily incorporate both into sketching tool kit.