My 96 year old grandmom has developed a large bedsore/bruise on her coccyx that isn't going away. We think it is from spending much of the day sitting in her armchair. I recently learned of ROHO cushions as a good remedy for pressure sores, but there is such a variety of options available–– high/low profile, number of cells, contoured/not contoured. Many of them are evidently intended for wheelchair use. She still walks and occasionally uses a wheelchair when there is far to walk. I'm not sure how to choose the one that would be best suited to her situation. Are there any considerations with regard to the high/low profile issue besides seat height? Her present armchair is a good height for her right now, so I imagine she wouldn't want to go too high profile or she will struggle to get seated, but we could always get her a lower seat if higher profile cushions are better for some reason. Another potential issue is that she has a tendency to slide down in her seat when she puts her feet up, which is most of the time. So would that be a reason to get a contoured cushion––to keep her further back on the seat? Or would a contoured cushion be too restrictive for an armchair situation? Lastly, cost––holy cow these cushions are expensive ($350+)! In searching for them, I've come upon similar, but to varying degrees more affordable cushions made by other companies (Kolbs, Drive Medical Balanced Aire Adjustable,...). Are any of these any good? Or are there any you'd recommend? ROHO also offers a couple of drastically less expensive ones (their "MOSAIC" and "LTV" cushions are both under $100). Why the price disparity? Are they inferior in some way? Wow, long post! If you've made it this far, thanks for reading. I look forward to your advice!