Precision drill chuck for right and left rotation, ISO 7388-2 (JIS B 6339 MAS/BT), form AD/B. Short design with central coolant supply, made of alloyed tool steel. Taper according to DIN 254, hardened to 58 ± 2 HRC. With a tensile strength in the core of approximately 950 N/mm² and a hardness depth of at least 0.5 mm. Taper angle tolerance AT3. Surface roughness of the taper: RA < 0.001 mm. Runout accuracy ≤ 0.02 mm. Balancing quality: G6.3 25000 min⁻¹. Tensioning via hex key. Designed for holding tools with cylindrical shanks and internal cooling. Delivery: Includes sealing ring for coolant channel drills Ø 3–6 mm.