Skinny can line and letter writing nib. Writing stable for low center of gravity design. 4 mm easy to rely on the ruler guide pipe. Knurled prevents hand slippage. A window display you can use core hardness.
◆ core diameter: 0. 4 mm ◆ internal core: HB
Axis: play ABS to gold, grip: brass clip: iron
Erase replace :Z2-1 N