JOSEF SEIBEL Fenja 01. A Shoe as pliable as these slip-on ballet-style pumps are bound to be lighter than most but the real revelation is its extraordinary comfort. Made from super supple, high-quality leather allows for elasticity that contours to the foot. Sitting atop a rubber sole offers robustness given its flexibility. Slip into a pair of Fenja 01's and you will feel like you are walking on air!