Case Size: 1/33.8 fl oz. Wan Ja Shan Vegetarian Mushroom Oyster Sauce is a savory, plant-based sauce, perfect for stir-fries and marinades. Wan Ja Shan Vegetarian Mushroom Oyster Sauce (1200 g) is a rich, plant-based alternative to traditional oyster sauce. It brings a savory, umami flavor to stir-fries, soups, and marinades, offering a delicious vegan-friendly option.