The back length, measured without the shoulder straps, is 57 cm. It's a size L, but it fits like a size M and isn't oversized. It's from a few years ago, but I've only worn it about 4 times, just in the summer. Airism material beige slip, comfortable to wear. - Material: 80% nylon, 10% polyurethane, 10% polyester - Size: L (Bust 86-92cm) - Color: Beige - Design: Slip Thank you for looking.