Bear Glass recommends the ClearShield system helps to protect your glass surface. Metal rust, water spots make your glass surface hasty and unclear. Mostly the window glasses and shower doors suffer from such problems as they remain exposed to water or the environment. ClearShield helps save glass surfaces from any kind of stain or watermark and make it look like the new. For any inquiries about ClearShield, please call 718.832.3604 or email us at BearGlass@yahoo.com.