These leg irons are huge!  The diameter ranges from 120mm to 67mm, depending which of the 22 locking positions you choose.  They weigh 1330 grams (over 2 pounds), making them the heaviest Western style leg irons which we stock.  They are double locking with the pin on the oversize key which is much bigger than the standard handcuff key but similar to look at.  The gap between the two 'cuffs is 32cm.  Yes, these are better known as overboot leg irons.