Essential Connector Piece – Designed exclusively to attach Glow On and On Cartridges to the Glow On and On Shower Head Leak-Sealing Ring – Built-in rubber ring ensures a secure,gap-connection for stable water flow Quick & Simple Installation – Tool-assembly makes attaching and replacing cartridges fast and easy Lightweight & Durable – Made for everyday use while maintaining strength and stability – Tailored fit ensures smooth performance with Glow On and On Shower Cartridge products.