These are the heaviest model of the new Clejuso line of handcuffs. In principle one could obtain a handcuff key by filing off the extra part on the shackle key. The modified handcuff key actually has a part of the edge filed off.
Foot shackle key opens foot shackle, handcuff keys open handcuff as one does expect.
The foot shackle key does not open any handcuff. Any key will open the single-locked leg shackle. Now the louble-locked legiron is the interesting case. It seems that the extra piece on the foot shackle key disengages the double lock. No problem with the proper key of course.