Tether line indicator is the first component of TFS trading strategy. It was named this way because stock prices have a tendency to cluster around it. It means that stock prices tend to move away from the midpoint between their 50-day highs and lows, then return to that midpoint at some time in the future. On a chart, it appears as though the stock price is tethered to this line, and hence the name.
You can change long to short in the Input Settings WARNING: - For purpose educate only - This script to change bars colors.