Specific for # 54900 & # 54901 high speed handpieces. D*Tach™ helps relieve the strain for pressing the push button of the handpiece. The D*Tach™ makes inserting and removing burs simple and easy. If burs are not seated completely in your handpiece, it can quickly cause damage to the turbine. D*Tach™ can extend the life of the turbine.