We have used Dove sensitive skin body wash or bar soap on her for years. Was very hard to remove, damaged my walls. Holes in the sides help with ventilation, a big plus here in Phoenix. Make sure you have the pre drilled holes on the correct side when assembling. Working out in it is amazing you wouldnt even noticed you have it on. Comfortable fit, not had this type of Birkenstock before so allowed for different style. Inconvenient but if youre made it this far you obviously cant resist. With socks theyre too tight, but I planned to use them with bare feet. I tried some of the settings, and there are a number of them. I keep experiencing problems with the device.