Bling for fish, although they may also be found attached to mangroves, pontoons jettys, and all manner of underwater structure. Made by Marukyu (http://www.marukyu.com), branded as Ecogear in Australia. Not necessarily the best bream hardbody lure ever made, but so popular that in Ausbream polls they catch twice as many fish as other lures (ie more people use more often so they catch more)
Oddly enough, if you check the Marukyu website you won't find them. The 48F and 60F are there but not the 40F. My guess is that the 40F would outsell the other two at least 3 to 1 in Australia.
BTW, I recently bought one of their CK40F07 - chubby version of the sx40. Haven't given it a run yet. Looks very like a Jackall Chubby, which is another flavour of the month, or a Manns 5+. Will report how it goes when I try it.