Made of Stainless steel, durable and healthy. With shaker bottle/cup, makes your nutrition dissolve more totally and quickly. Makes your drink mix uniformly, suitable for most bottles with cover. Put the stainless ball into the bottle and cover, then shake it uniformly. The protein shake blender ball is not easy to be rusted and is convenient to be washed. Material: Stainless steel. Color: Silver. Size: 5.5x4.5cm. Package included: 5x Shaker blender ball. Mixer ball for shaker made of food grade 304 stainless steel, indestructible,not rust and easy to clean. The blender ball can ensure nutrition dissolve more totally and quickly, you do not have to use a blender just drop a ball into your shaker cup. If you hate those protein or matcha lumps , this shaker ball is the perfect mixer ball for you, but if your drinks are even thick, shaker ball might not swish around much in the drink. Suitable for most of bottles with cover, Put the stainless cylinder into the bottle and cover, then shake it uniformly.