This is for your information only - and I'm not posting this to support these "sticks"
I think they are a waste!
I know the guy who makes these personally - by coincidence (yes, that photo is him). He is part of a local gold prospecting & MD'ing club.
I stopped by his shop last week, and he was telling about making 4-6 CO Au Sticks, and he was about to ship them to the UK. He was soldering something with two tone alerts on it (and LEDs). The small tone producing box, produces one of either two tones (supposedly one for silver, and the other for gold). He asked if I had a gold ring on (yes), and then turned on this tone box, with the audible tone for "gold". He then walked around with what looks like the water hunting two coat hanger trick (i.e. dowsing or water witching). Supposedly the tone causes either gold or silver to be detected by the dowsing rods (I have STRONG DOUBTS on the physics of this). I am using the term "dowsing", but he disagreed with me calling it that. Anyway, he replied to me by showing me his hand with some large silver rings on, and claimed he found them with his "CO Au sticks". We agreed to disagree, and I dropped the argument.
I had gone through a couple months of dowsing with a metal detecting friend back in the early 1980s. It didn't take long to give it up
That became an exercise in digging empty holes, and finding strange things other than what I was supposed to find. Once I was trying to find buried gold, but dug up some cigarette cellophane, which seemed to attract the dowsing rods (ha ha!). I did NOT buy them, but rather made them from bent welding rods.