Cut the old tube flush with the outside of the earpiece. Insert a tube-lock tool into the base of the earpiece and push the remaining tube and tube-lock or TRS tube out of the earpiece through the canal tip. Make sure the sound bore is free of any obstruction.
Insert a wire tube puller into the sound bore from the canal end.
Thread the quilled end of the tube-lock or TRS tube through the tube puller and then pull the tube into the earpiece.
Pull the quilled end of the tube and gently work the tube-lock or TRS sleeve into the earpiece.
Continue manipulating the earpiece and tube until the tube-lock or TRS is approximately 3 mm below the outside surface of the earpiece. Once the tube is in the proper position, trim the excess tube from the canal end and refit the instrument.