Yellow

Printing this material

• Abrasive — Contains fibre, mineral or metal filler that wears brass nozzles quickly. A hardened or ruby nozzle lasts; a stock brass one may not survive a spool.
• Keep dry — Absorbs moisture from the air, which prints as stringing, popping and weak layers. Filament that has sat out usually needs drying before use.
• Flexible — Soft enough to buckle instead of feeding. Direct-drive extruders handle it; long Bowden paths often will not.

True of TPU generally. Follow Amolen’s own guidance for this spool.