All incoming raw materials—including ink, tips, tubes, metal components, and plastic parts—are subjected to rigorous initial checks. This includes safety and viscosity tests for ink; dimensional tolerances and finish inspection for metal parts; and visual, dimensional, and assembly compatibility assessments for molded plastic components.

Once components pass initial inspection, sub-assemblies undergo a Function & Durability Check (FQC) to ensure underlying parts perform as intended together.

Assembled products are audited through a final QA phase.
Each finished highlighter undergoes a concise but rigorous testing sequence.

Sealed bodies are pressure-tested to ensure no leakage, validating reservoir integrity.

Manual or torque checks confirm the cap resists loosening.

Each unit is tested, e.g., writing until ink depletion to verify claimed stroke capacity.

Finished units in sample boxes are dropped to simulate shipping impacts.

The tip is compression-tested to avoid deformation or flow disruption during use.