Capacity and stability: check the maximum load(often 300–400 lb / 135–180 kg) and the width of the steps.
Basin compatibility: wall size/height (48", 52", 54"), presence of a terrace(simple scale vs indoor/outdoor “A” scale) liner (anti-wear pads).
Security: handrails, closed risers (to limit entrapment),anti-intrusion kit(lock), surfacesnon-slip.