Check the listing for details. 16 in. x 17.50 in. Polypropylene White Octagonal Gable Vent. Condition: New. Listed at 39.09 USD. Novik's 16 in. Provides optimal airflow while keeping weather and insects out. Includes an exclusive lock-on system that eases installation and has 3 locking positions - 3/4 in., 1 in., and 1-1/2 in.