1.best quality for 6"~17 1/2" 2.high quality,best price ... :4,5,6,7,8,9,... Specifications1.best quality for 6"~17 1/2" 2.high quality,best price 4 ... 4,5,6,7,8,9,... 1,Application:1,Suit for drilling medium to medium-hard formations.2,Evolute asymmetrical blade ... cooling and cuttings evacuation requirements with available hydraulic flows.Allows for higher flow rates with minimal increase in pump pressure. ...