The unit I used when I had an injury had larger plastic or rubber feet on the ends of the legs. With the weight spread out among 4 points, I would think it would be much less pressure than a person stepping into the tub or shower and having all their weight on one point.

I honestly wouldn't worry about it as long as the legs had some sort of feet or cap on them. Now, if it were just a metal tube, that would be a different story.

Our house was built by husband's grandparents in the 70's and they and his mother lived here until about 10 years ago. The fiberglass tub in our house's only remaining original bathroom has a patch in the bottom from when DH's grandmother's shower chair poked through the bottom. So no, I would not put a shower chair in a fiberglass tub.

I figured it was a possibility - just wanted to confirm. But I realized today that I was looking for the wrong thing. I was looking for shower chairs to put in a tub. I should have instead been looking for bathtub seats. Instead of sitting on the bottom of the tub with legs, they rest on the edge of the tub and clamp on. Think this will work better for my purposes. Thanks for the responses everyone.

look at the chair at walmart. very reasonable, adjustable height, holds up to 350 lbs...generous rubber feet...

Has anyone used a shower chair in a fiberglass shower.