This type of current transformers has a specially shaped through window for its secure mounting to a current carrying busbar or busbar assembly of an appropriate size. In some models, the window has a complex figured shape, which allows the transformer to be mounted on buses of various standard sizes. Therefore, when choosing ASK current transformers on our website, filtering is provided for two standard bus sizes - the main one (Busbar 1) and the additional one (Busbar 2). Since any transformer with a window can also be used to measure the current in a cable, it is possible to filter by the maximum diameter of a cylindrical conductor (Cable) that passes into the transformer window. Along with these characteristics, the selection of measuring transformers is carried out according to all other defining parameters: primary and secondary current, burden and accuracy class.