In our system, your Tool Designer, has a wide choice of thickness in BC, with symbol 'R' & 'S', in support plate with symbol 'D' & 'E'. Further cavity and core plates 'A' & 'B', plates have wide choice for thickness to select most appropriate thickness for the tool being designed. The last figure in bracket is the height of rail.
Standardized Mould Base Overview
Normalien Standard Mould Base (NSMB) Sizes
Identification Of Part For Standard Mould Base