Angle iron with lengthwise/longitudinal slots 7x30mm on one side for universal support. Can be used to support cable trays, cable ladders and electrical installations. es in the industrial environment. Edges and bolt holes are not rounded or otherwise prepared. This publication is intended as a practical guide for the proper and safe* installation of cable ladder systems, cable tray systems, channel support systems and associated supports. (hereinafter referred to as "Handan Jinmai Fastener Manufacturing Co. ") specializes in the production of high-performance angle iron, specifically designed for power fittings, fiber optic cable line accessories, and iron accessory systems.