... best price 4.number of blade :4,5,6,7,8,9,... 1,Application:1,Suit for drilling medium to medium-hard ... underground foundation workFormationsticky, soft, medium hard, hard formationblade4,5,6,7,8,9Packingwooden boxPayment TermT/TMOQ1 PieceSupply Ability1000 Pieces/monthDelivery Timewithin ... production technology ensuring the quality satisfy international request. API 8 1/2" metrix body PDC bit