Product review (4 stars): my husband is satisfied with this 8fit vent duct hose
This Flexible Pvc Vinyl Vent Duct Hose, is a thin, light duty, typically lighter in weight, thin wall, extremely flexible, and designed solely for blower type applications to move light airy product, (as compared to heavier duty "material handling hoses" which have a thicker wall and are used in pump-type applications) economical vinyl air vent or blower hose. So we  used  in our  bathroom fan (can be used in AC or humidifier units ) that we just installed this winter during bathroom renovation ,Fits right in without any issue,my husband is satisfied  with this 8fit vent duct hose.
  Although not recommended due to dryers
I received this product at a discount in exchange for my unbiased and honest review, which is what you read above!