Window Guard Rail Installation Guide: List of Assembly Parts: Window Guard Rails – 2 Nos. Supporting Knobs with Rubber Pads – 4 Nos. Binding Screws – 6 pairs Assembly & Installation Guide Step 1: Measure and make note of the window width on which the rail is to be installed Step 2: Adjust the rail width to match the window size and use binding screws to secure both rail frames together, one on top of the other (As shown in pic) Step 3: Place window rail on location, insert supporting device with knob and rubber pads into four open corners of the rail Step 4: Rotate knob in a screw motion for the rubber pads to press on the window sill. Pro-tip: Tighter fastening of the knobs will hold rail securely in place.