There is a horizontal bar in the back that prevents the knees being bent. Absolutely annoying. Unfortuneatly, I bought them for the mic. It?s a great novelty case for my AirPods Pro, the only downfall is it has the hook in the back covering the pairing button. After the first time they open and close just fine. The metal is breaking and when tried to contact the seller no answer They are warm and look good on my feet. Per me Birkenstock è una garanzia , ho lo stesso sandalo in diversi colori Very comfortable and nice looking. Il loro design è sobrio e senza troppi sfarzi, rendendole adatte sia ad una postazione tamarra che ad una minimal.