The barrel is solid aluminum rather than plastic

The barrel has a built-in window so you can see how much ink is left

and clean sketch outlining

Weight: 198g

uni pin fine line pen light grey Size:0.1 The barrel is solid aluminumThe Uni Pin Fine Line Light Grey lays down a soft, cool grey rather than a strong dark tone, suited to faint shading, base sketch contours, or subtle drop shadows behind darker title text where a full black or dark grey line would feel too heavy. The tip is a steel guided polyacetal core for a steady, consistent line. The ink is uni ball's "Super Ink" pigment formula, archival and waterproof once dry, so it can sit underneath a watercolor glaze