This is a remix of Core ONE Vent Flaps, using a dryer-style gravity flap mechanism to help retain chamber heat when the exhaust fans are off.

The flaps pivot open when airflow from the exhaust fan is present, and automatically close under gravity when the fan stop. When closed, they block the exhaust outlets to reduce passive heat loss. When open, they allow exhaust airflow with minimal restriction.

This helps maintain higher chamber temperatures for materials like ABS, ASA, and PC, while preserving normal exhaust behavior for PLA and other low-temperature filaments.

Ignore the bad heat insulation on my printer. The flaps works very well.