Suction cup is 3.8" Diameter; minimum tile size 4.25 inches; confirm compatibility with bath surface. Re-apply suction clamp prior to each use to ensure proper locking, prevent falls, increase stability. Suction will not work over grout lines, gaps, cracks, uneven surfaces; easy to install and remove. Easy to apply and remove; temporary Modular design; portable, travel friendly bath safety grab bar. Hospital grade materials for care givers, the disabled, seniors, injury recovery, assisted living.