Berin Unique and effective - These are really cool! I received these for free in exchange for my honest review.. and truth be told I was a little skeptical about them. But, after some use I can confidently say I’m a believer! They are easy to trim down to your shoe size, and once in your shoe are quite comfortable. I’ve worn them in crazy hot and humid temps and love that I don’t have to battle with no shoe socks slipping down around my foot, yet my feet don’t get sweaty and stinky like they do when I go without socks in my shoes. Best of all, they are washable (and hold up well!). I highly recommend and am getting more for family members. A truly unique and smart invention.