The holder is easy enough to press onto the vent slats on a BMW i3 and a Prius V. It holds tight and will not fall off. The mechanism to hold the phone is simple and only one hand is needed to insert the phone in the holder. It can hold the phone either horizontally or vertically and no acceleration, braking, or rough roads will dislodge it. The holder has a little space between it and the vents so air from the vents can pass around it. However, expect the phone to approach the temp of the air from the vents. I like that the holder is close to the vents because the closeness minimizes the strain on the vents created by the weight of the phone.