THIS WILL FIT THE NEW MODELS WITH THE SLOT DRIVE SPINDLE. OLDER MODELS WITH OUT LED LIGHT TAKE THE HEX DRIVE ADAPTER. YOU ARE BUYING A NEW HOUGEN (Made In Spain) DRILL CHUCK AND ADAPTER FOR HOUGEN DRILLS ( HMD904, 905 & 927 (SLOT DRIVE) ) THAT HAVE A SLOT DRIVE SPINDLE,THIS IS EVIDENT BY THE WAY THE ARBOR ATTACHES TO THE MOTOR SPINDLE. THIS WILL ALLOW YOU TO USE TWIST DRILLS WHEN NEEDED,ESPECIALLY USEFUL WHEN DRILLING HOLES THAT ARE TO BE TAPPED OR FOR COUNTER SINKING HOLES.THIS CAN BE CHANGED FROM THE ANNULAR ARBOR TO THE DRILL CHUCK IN LESS THAN 5 MINUTES. YOU WILL RECEIVE THE FOLLOWING ITEMS 1-HOUGEN ADAPTER MODEL # 08186 - HMD904, 905 & 927 (SLOT DRIVE) 1-HOUGEN (MADE IN SPAIN) DRILL CHUCK W/KEY HOUGEN PT.#10731 1-INSTRUCTION SHEET ANY QUESTIONS EMAIL OR CALL 206 878 1148