There are normal three kinds of coverlayer of flexible circuits(flexible pcb), please see below thickness:

1)12.5UM:     PI：12.5UM    AD：15UM           Thickness：27.5UM

                         PI：12.5UM    AD：25UM           Thickness ：37.5UM
             
2)  25UM:     PI：25UM     AD：25UM            Thickness：55UM

If you need any other information of flexible circuits and flexible pcb, please contact us anytime.