I'd like to get one of those arms also.
My transducer cable is way long however.
Might have to get creative.
For now I use a suction cup mount and coil the excess cable around the base of my 522c Lowrance.
I routed the transducer cable from the transducer to the inside of my hull, following my power cable, then coiled the excess cable inside and came out of the hull through the same hole and followed the power cable up to the head unit. I hope that makes sense. Basically there's a loop of excess transducer cable stored inside the hull that is routed through the opening that my power cable utilizes. I didn't like the idea of having a bunch of excess cable coiled around the base of my RAM mount. I'm an electronics technician in the Coast Guard and having all that excess cable out and coiled just didn't sit well with me due to my training. Too much to get hung on or snagged on objects while fishing/hunting.
I'll try and get some better pics of my install and get them posted up.