Cisco TMSBZ-L Trolling Motor Stabilizer Mount – Large, 12 in. – 17 in.Safely secure any trolling motor arm from 7/8 in. to 1-3/8 in. in diameter with no tools requiredAllows positioning of the unit along any position on its horizontal, vertical, and radial axisExtremely easy to use and heavily constructed for a lifetime of useThree sizes available, measure from the bottom of the round plate to the bottom of the trolling motor armLarge – Adjusts for any height from 12 in. to 17 in.