I just had a look and the product is pretty much a 100g/L GA3(Gibberelic Acid) solution. I wouldn't spend too much on it I think I bought 100ml of 130g/L for $12 a few years back, I have used less than half of it. You really don't need much.
I used it on a few different difficult species to germinate and not limited to cacti. Overall I found it did increase germination and most definitely induced flowering on some cacti.
Personally unless you have a specific purpose I would give it a miss.
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