Holy crap, Batman! I have never seen or heard of one of these before. Absolute gold.... I need to have one. Who wants to put money on there not being any in Australia?
For your sake I hope they are available Down Undah.
There is one warning that goes along with using a torque multiplier ... you've got to "know your own strength" (so to speak). Using a (let's say) 3:1 multiplier essentially makes you 3x stronger. If you're not observant and careful, it becomes very easy to snap a bolt right off. So I would not suggest using one except in situations where fastener torque needs to be above ~around~ 150 lb/ft of torque. Even so, care must be taken.
Multipliers are also very handy for busting loose large fasteners, such as large lug nuts on heavy vehicles.
If I recall properly, multipliers are used mostly in the oil fields, especially on pipelines where mating two large pipe flanges requires very high torque levels. These are very large fasteners (like 1.5" diameter and above) that mate lengths of high pressure pipeline together that will be subjected to high internal pressures and temperatures. Think oil, and liquefied natural gas. They're also used in ship yards, railroads and rail yards, off shore oil rigs, and refineries. Just to give a little context and background on the device.
But they can be easily applied to motorcycle maintenance, repair, and fabrication just as well. Kinda like having that big bastard of a guy in your shop who's good for heavy liftin' and busting loose large, high torque fasteners. Handy when needed, but applied with discretion.
Thing is, if it only gets used one time in your shop, it's well worth it's cost. "Better to have it and not need it, than to need it and not have it" ..... kinda like that shotgun in the closet.