Poorly machined holes can result in damage that causes unreliable output or even total failure. The transducer mounting hole drill kit contains the necessary drill bits and taps needed to machine a standard transducer mounting hole, including a special pilot drill required to machine the 45 degree seat. Drill kits are available for the 1/2-20 mounting hole (KF12) and the M18x1.5 mounting hole (KF18).