Black chiffon blouse by lady sloth. I don't know the specific name. 

This blouse features elastic neckline, waist and sleeves. It's very comfortable and easily fits an AU women's 16.

The flat measurements are as followed:
bust and waist (stretched) 65cm
arm width (stretched) 28cm
arm length: 67cm

proof photo displayed on a mannequin set to 
bust: 110cm
waist: 80cm

Pet free smoke free home. No obvious signs of damage