System 3R OEM 3R-321.46 MiniBlock System 3R OEM 3R-321.46 MiniBlock Manual hydraulic chuck for vertical or horizontal mounting on the machine table. – Fixed index positions 4X90 degrees. – Weight 2.3 kg. For Rapid Holding Systems Compatible version click the link below System 3R 3R-321.46 Mini Block, Manual Hydraulic Chuck Compatible. Rapid Holding Systems designs and engineers the best System 3R compatible Tooling. High Quality 100% Compatible System 3R Gauging Devices, Chucks, Holders, Drawbars, Pallets, Plates, gauging devices, and self centering devices. Checkout the price of RHS Branded System 3R 3R-321.46 Mini Block, Manual Hydraulic Chuck Compatible.