The vertical suspensions alternate in size. I'm guessing 10 inch and 17 or 19 inch diameters. There are 26 to a string. The horizontal double strings have 42 suspensions all the same size, either 17 or 19 inch dia. There is a ladder right up the middle of this tower. Anyone who wants to check my guesstimate of the diameters is welcome to go up and measure them. I'll stay on the ground and take the picture thank you very much !