The insoles are thin, if you add an insert or anything they might not be able to handle it where the fabric is attached to the bottom of the shoe. Something youd get from a £15-25 headphones. I wear an 8 and ordered a medium. The XL will not fit a size 11-12, they are fit for a 9-10. Garufi biked across America, and did it on his own terms, his own way, which really spoke to me. I would term the new ones “plastic” shoes. They are comfy enough to walk around all day on my day off - no arch support issues, no rubbing at the thong between the toes or along the top of the foot by the straps. Possibly money, specifically deals not coins. The only thing I can compliment is that at least the hole is off to the side and not in the center. Decided it wasnt enough of a negative to return, so i tried it on.