One end of the Keepeez features a sturdy buckle-lock for secure fastening to strollers, car seats, high chairs, and shopping carts. The opposite end keeps drinking accessories tightly fastened with the adjustable, spring-powered push-button locking mechanism. This attention to detail guarantees a product that is effective and easy for parent to use. – Boy Color The Nuby BPA Free Keepeez Sipper Gripper- Boy Monsters Features: BPA Free 4 and up months Childproof push button Keep sippy cup close and clean Adjustable strap attached to strollers, car seats, high chairs and more.