This Jacobs DIN 371 rigid tap collet with overload clutch has a tap size no.1 of M4 with a 2.8-mm tap shank and 2.1-mm drive square. The Jacobs DIN 371 rigid tap collet features a quick change style allowing taps to be changed quickly. The Jacobs DIN 371 tap collet's rigidity provides reliable and easy use for general tapping applications while the torque structure limits can prevent breakage. The Jacobs DIN 371 tap collet is used for air tapping. Like all of Jacobs chuck's products the Jacobs DIN 371 rigid tap collet includes a one year factory warranty