Use these lasting hinge covers and you'll save up to 90% of the cost of a colored backboard system — and with colored covers, the planner or installer can color-code individual blocks instead of working in groups of four or eight. Made from flame-retardant thermoplastic, the covers protect the quick clips and provide a convenient surface for marking circuit designations. Each cover is hinged and can be easily removed and replaced. There are two depths for the covers; the standard-profile allows for standard plug-on accessories, and the high-profile cover allows for larger accessories such as the Colored Bridging Clips.