I've never seen a floating one before but that probably makes sense in a commercial fish cleaning operation. It looks like the double hardened steel rods set an angle with springs to give them tension type "butcher's steel" several companies sell to meat packing companies. As such, it wouldn't take any more metal off than a standard polished steel. I have a couple around here I've tried in the past. They work about as well as any polished steel for quick touch-ups.
Yeah, I believe it is the standard "wall mount" model, it just happens to have a plastic base that kinda floats in his shallow tub. More convenient for him to fish it out of the bath than to have it mounted behind him, plus it probably stays cleaner this way.
"God sends meat and the devil sends cooks." - Thomas Deloney