These hinged alluminium handcuffs were patented by the Yuil Corporation in 2000.  They are incredibly light at 179 grams but are also very strong and robust. Law enforcement officers have enough to carry on their belts as it is and the weight saving associated with these handcuffs is a real bonus.  Double locking with the pointed bit of the key they are fully secure, especially with the non standard two independent lever lock.