This video has step-by-step instructions on how to install a universal trimmer head as well as replace the trimmer line.
Start from the beginning to view installation.
Skip ahead to 2:58 to view line replacement instructions.
The universal trimmer head fits many brands of trimmers including Ariens, Astron, Brush King, Bunton, Dolmar, Echo, Red Max, Robin, Ryan, Ryobi, Shindaiwa, Snapper, Stihl, and Subaru. Check out our master chart to find out which kit your trimmer needs.