"It is expected that these cuffs will endure more use than an average set of handcuffs so all of the components were heat treated for strength and longevity. Use of a key has been replaced with a low profile dial which opens the cuff when turned in the same direction as would be used if one used a typical handcuff key. This feature is useful as it provides training in turning a key in the proper direction, thus reducing key breakage. The face of the dial provides an illustration indicating the direction to turn to open the cuff. Additionally, the double lock feature of the cuffs is fully functional if use is desired."Nickel finish, no keys included- you don't need them. Weigh 10 ounces.