A thumb ring built into the underside of the case lets you hold it steady in one hand while painting with the other

An incredibly simple but clever invention from Molotow

Dust filter (FFP3) with a built-in thin carbon filter

Ink: Acid-free permanent pigment — waterproof when dry

It can be filled with all kinds of fluid inks or water

uni ball um 153s gel impact 0 1 roller ball pen Colors:Red A thumb ring built intoThe Signo Gel Impact uses a 1. 0 mm tungsten carbide tip, broad enough to glide across the page with minimal drag rather than scratching the way a finer rollerball tip can. The ink is uni ball's gel formula with "Super Ink" technology, which bonds chemically into the paper fibers rather than sitting on the surface that's what makes the line water resistant, fade resistant, and difficult to alter or erase once it's dry, a relevant point for anything