Safety Rail Guard Ã¢â‚¬â€œ U Clip Installation Guide Pro-tip: When securing safety rail on staircase openings or against pillars, use a U-clip instead of a supporting unit. Step 1: Assemble the U-clip and knob (included with the safety rail packaging) into a single assembly. Step 2: Place a U-clip with a knob in each of the four corners of the safety rail. Step 3: Turn knob to press U-clip into pillar or handrail surface for pressure support. To ensure a safe grip for the rail guard, tighten the knob as much as possible.