Zinc Plated Steel DIN 3 Rail, 7.5mm Deep, 1m Long. Mount terminal blocks, power supplies, relays, and other control and distribution devices on walls and other flat surfaces and in enclosures. DIN 3 is the most commonly used rail. Rails with a bracket create extra space behind them to accommodate bulky items. Rails with an angled bracket are tilted, letting you fit more of them into a vertical space. For easy access, position high-mounted devices so they�re tilted downwards and low-mounted devices so they�re tilted upwards. On rails without mounting holes, drill holes where you need them. Rails with a centerline guide where you should drill.