CRL's Glass Extension Bolts were designed for projects that require thicker panel connections. Made from 316 Alloy Stainless Steel, these component parts are designed to work with CRL's RB50 and RB51 Double Arm Glass Fittings. Stainless Steel Advisory: Although Stainless Steel is resistant to corrosion, it is not rust or stain proof. CRL recommends periodic maintenance to help maintain its factory finish.