Many multi-pen sets include rubber or contoured grips, full‑length comfortable grips, and ergonomic barrel shapes (for example, hexagonal barrels) to help during extended writing.
Erasable thermo‑sensitive ink is removed by friction (the pen eraser) and can become colorless at higher temperatures (noted above about 140°F). Cooling (for example, placing it in a freezer) can restore the color. Because the ink can disappear with heat or friction, it is not recommended for legal or official documents.
Tip thickness is shown both numerically and with descriptive labels. For example, 0.7mm tips are often called fine or medium, while larger sizes such as 1.6mm are typically described as bold for a stronger line.
Drying times vary by formula: some gel inks advertise '3x faster' drying or claim times as short as about five seconds, while others do not specify. Quick‑dry gel formulas are noted as a smart choice for left‑handed writers.
Some pen sets use renewable or reclaimed materials for barrels (noted as wheat‑straw/renewable and reclaimed material), and packaging is sometimes printed on FSC‑certified paper using soy‑based ink.
