ToggleSwitch not worked in windowsphone7.5

Question

I used ToggleSwitch control in windowsphone, It works fine in windowsphone7 version, takes Microsoft.Phone.Controls as a assembly reference. But in the windowsphone7.5 it asks assembly reference for ToggleSwitch control, it's not included in Microsoft.Phone.Controls. Anyone know the assembly reference for windowsphone7.5 ToggleSwitch control.