The 2 Watergeeks Water Bottle Filters are designed for metal bottles with a 1.75" neck size, making them compatible with a wide range of bottles. Made of durable plastic and weighing only 2.5oz each, these personal filters can filter up to 600 bottles of water. The set includes 2 filters, each measuring 4" in height, and are manufactured in China. The Watergeeks filters provide a convenient solution for staying hydrated on the go while ensuring clean and safe water.