I bought an aftermarket one by Benvento (sold by IPD) and did not like how much it protruded above the roof. I felt as though it would blow off at speed, and it generated its own wind noise because of it's height. I returned it and bought the Volvo accessory one from Brentwood Volvo. It stuck up much less than the aftermarket one, and the leading edge is very low to the roof. It is made to fit the car. The aftermarket ones are "trimmed" to fit our cars. Trimmed differently along it's edge it fits a lot of other cars. The difference between the two in appearance and fit is like night and day.