THE JACOBS 16N 3JT IS A BALL BEARING SUPER CHUCK, A HEAVY-DUTY INDUSTRIAL DRILL CHUCK FEATURING A 3JT TAPER AND MOUNT. IDENTIFIED AS MODEL #16N, THIS CHUCK IS ENGINEERED FOR A CAPACITY RANGE FROM 1/8" TO 5/8" (3-16MM CAP). THE BALL BEARING DESIGN ENSURES PERFORMANCE FOR DEMANDING DRILLING APPLICATIONS. THE UNIT IS TYPICALLY PAIRED WITH A 5MT X 3JT ADAPTER.