Measure the width of the space between the vent directional vanes in a full-open (i.e. straight ahead) position. If the space between the vanes is 1/4" or more, it will fit.
For example, the center-dash vents on a 2003 Ford Explorer Sport Track are 3/16" (6/32") apart, fully open. This vent car mount will not fit, since the tabs that clamp onto the vanes are 7/32" tall (both top and bottom). The left-and right-side vent spaces are 1/4" (8/32") apart, and the vent mount slides right into place. That extra 1/16" (2/32") between the center and side vent vanes makes all the difference.