If you have a stall shower, for example 36″ x 36″, then I would suggest that you use a 18″ or 24″ grab bar at the entry point of the shower, hung vertically. In addition, use a 24″ grab bar hung horizontally on the back wall. By doing this you will ensure that you will be safe and maintain your balance. I would also suggest that you have your towel bars replaced with ADA Towel Grab Bars or a grab bar so they will be safe when stepping out of the showe.