The center hole on the fan blade for your Ventline Vanair Trailer Roof Vent w/ 12V Fan # VP-543SP is 0.03" in diameter. For a replacement fan blade, you can use the:
-Replacement Fan Blade for Ventline Vanair Trailer Roof Vent # BVD0217-00.
This fan blade measures 5-3/8" in diameter, and will work with your VP-543 as well as the VP-542 fan. view full answer...