I recently moved into a 15 year old house. The shower handle is one of
those one-piece units that you pull out to get water (the more you
pull, the more water you get) and turn clockwise or counter-clockwise
to vary the temperature.

Without knocking out the wall, how can I determine if I can replace
this handle with one more easily used? I've been told the current unit
is a Delta.

Thanks for any help.