Have bought and installed 2 of these for a 9鈥 chartplotter. Work great so far. I think the next size up (2鈥 ball) is recommended for bigger than 7鈥 units. If the angle is awkward and the setup mostly sideways, coupled with hard pounding on really rough water, the recommendation to go bigger for say, 9鈥 to 12鈥 units is probably correct. Would buy again, especially for 5-7鈥 gps/sonar units.