Bink 21oz Bone Day Bottle Borosilicate Glass Water Bottle Hydration Tracking The Bink 21oz Bone Day Bottle is a sleek and modern water bottle made of borosilicate glass, perfect for cold beverages. With a solid gray color and a twist lid, this round bottle includes a silicone and glass construction, making it durable and easy to clean. The set includes a lid and straw for added convenience, and it is machine washable for easy maintenance. The 21oz capacity is ideal for hydration tracking, and its stylish design is suitable for adults looking for a high-quality water bottle.