Ive also had surgery to repair a broken ankle and have several knee problems (infrapatellar bursitis, Osgood-Schlatter disease & Patellofemoral pain syndrome) so I go out of my way to wear only comfortable shoes. They mailed me a few more straps in case I lose another one. These are perfect for people who want Bluetooth buds but keep losing them. The quality of the sandal is still top notch. Very happy with my purchase and the price was great! I had these for 6 months now and just switched to a different retainer. I didnt measure it but I would guess it is about 7" x 10" not counting the 1 1/2" lip for tools. I havent found that to be the case however since the relaxed fit is wider than the roomy. That being said we will be using this primarily as shoe storage, not so much as a seat for ourselves. Just what I have been looking for.