The Smith & Wesson extra link handcuffs have an additional chain link in between the cuffs for a greater distance. The cuffs themselves are the same as the Model 100 double locking police handcuffs. They feature the slot double locking mechanism. satin nickel plating and exposed rivets for added strength. Satin nickel provides a dull cloudy finish in order to minimize glare in tactical situations. The additional link is useful when prisoners have difficulty bringing their arms together behind their back. The distance between the cuffs is 3 1/8. over an inch more than standard. MEETS NIJ STANDARD 0307.01 Specifications: Wrist Opening: 2.04 First Notch Inside Perimeter: 8.40 Last Notch Inside Perimeter: 5.80 Tightest Inside Width: 1.80 Weight: 10.0 oz Locking Positions: 23 Distance Between Cuffs: 3.25 Maximum Overall Length: 10.23 Two Keys Included