Kel-Met KM-2500 are made entirely of stainless steel. They are extremely rust resistant and are anti-allergenic. Outstanding fit and finish, they open with a standard handcuff key. The hinge is designed so the handcuffs lie flat when folded. The hinge opens to only 180 degress, providing more control like rigid handcuffs. 2 stainless steel keys included. Weigh 15.9 ounces. Made in Poland.