This part of EN 13126 specifies requirements and test methods for durability, strength, security and function of mechanically operated variable geometry stay hinges (with or without a friction system). By means of this European Standard, the user of recognized tested hardware can assume that with correct usage, the variable geometry stay hinges (with or without a friction system) for windows conform to prescribed requirements. NOTE 1 This European Standard is applicable to variable geometry stay hinges (with or without a friction system) whether fitted with integral restrictors or not. NOTE 2 Balancing stay arms/hinges do not represent a friction system. NOTE 3 For the purposes of this European Standard, the friction system is achieved by friction pads or similar.