3/8" I.D. Mas/Bt-30 Guhring Shrink Fit Holder With Conventional / Mql Coolant, 80Mm Gage Length Mas/Bt To Din Iso 7388-2 Form Ad | Balanced To G2.5 / 25,000 Rpm | For Tool Shank Tolerance H6 | Includes 4 Or 6 M6 Balancing Screws | Includes Setting Screw, Series No. 4977 Or 4904 | Suitable For Tools With Internal Coolant. A Gripping Principle: When Shrink Fitting Tools Into Shrink Fit Chucks, The Decisive Factors For Ensuring The Safe Clamping Of The Tool In The Tool Holder Are Solely The Heating And Cooling Of The Tool Holder. The Heating Process Expands The Shrink Fit Chuck Enabling A Tool To Be Inserted Or Withdrawn Respectively. During The Cooling Process It Contracts Again And Clamps The Inserted Tool With Maximum Clamping Force. Series No. 4739, Order Code 109.0300. Made In Germany, Guhring Part #9047391090300