Fluted sleeve standard on all models except 6200, 6206, 6204, 6208, 31138, which are smooth and ground. Jaws center-ground for absolute straightness and alignment. Jaws specially treated to ensure extended thread life and high gripping surface hardness. One-piece sleeve eliminates crack between driving teeth often found in other designs. Through-hardened sleeve teeth, nose, and keyholes for wear resistance. For portable, bench, or floor mounted power tools. At minimum capacity will hold a No. 80 (.0135in/.344mm) drill.SEPTLS4036200. TLS4036200. Jacobs chuck Jacobs chuck Medium Duty Plain Bearing Chucks - 6200.