System 3R Macro Compatible 2?? Square Precision Multi 4 Chuck Rail

System 3R Macro Compatible 2?? Square Precision Multi 4 Chuck Rail. Mini System Macro Compatible is a 2?? square chuck 56X56. 4 Macro chucks mounted to rail. Quality System 3r Tooling RHS Brand System 3R Macro Square Multi Four Chuck are 2?? square. Beneficial to save space if size constraints are a problem