Seco Tools India [P] Ltd. Offers Vibration Damping Shell Mill Holders. Seco Tools India [P] Ltd is an ISO 9001 and ISO 14001 certified company. The Vibration Damping Shell Mill Holders are designed for increased productivity, improved surface finish and longer tool and spindle life. The Vibration Damping Shell Mill Holders improve the dynamic rigidity of milling assemblies. This allows much higher cutting data, with quieter operation and optimum stability. The Vibration Damping Shell Mill Holders are available in a wide range of types and sizes like cylindrical, conically strengthened, HSK, Seco-Capto, DIN, BT and CAT.