Birkenstock Women's Oswego ShoeSize Chart Just slip in! The BIRKENSTOCK Oswego is a handy slip on shoe that will delight both men and women alike. The casual low shoe features elastic inserts which make it easy to put it on and take it off in no time. The flexible rubber sole with a shock absorbing cork PU intermediate layer and the padding at the edge of the shaft result in even more comfort. The upper is made from especially soft suede which hugs the foot like a second skin.