Hello The sash window restrictor are not long enough to reach the second sash i.e. the gap between the two is greater than the length of the pin. It would have to be a very close/accurate fit for these restrictors to work effectively more akin to modern sash installations rather than our 'sloppy' 120 year-old windows. I had to fit an additional piece of wood to lessen the gap...this was disappointing as it has spoilt the look of the refurbished window to some extent. Hello Just to let you know that the pin sheared the first time the restrictor was used.....weak fabrication and poor quality and really not fit for purpose