Most non-professional tennis players will serve their second serve with 10 to 20 MPH less speed than their first serve. – Bill Gerk, Burlingame, CA, USA
A cool tool is anything useful that is superior to comparable items. If you think this tool is inferior suggest a better one. You are welcome to insult a tool, but comments containing insults to individual people will be deleted. Corrections of fact are always welcomed, if stated politely. Recommendations of better tools are dearly wanted and may be elevated to the front page.