The "S" cowl vents are made of flexible PVC (polyvinylchloride) which has very good UV resistance, revolves, and is removable.
On "S" model vents, the ring nut (collar) is secured by fasteners.
The included ring nut (collar) and mating deck flange (attaches to dorade box) is made of a hard plastic.
An insect screen and solid stainless steel cover plate to close off the cowl vent can be purchased separately. See Accessory Products, below.
The accessory Dorade Box (sold separately) mates with the cowl vent ring nut and catches and drains water that enters the cowl.