8030-RRK-100. The Symax Class 8030 Type RRK100 provides the mounting slots for the SYmax model 300-700 processors, 16-64 function I/O modules, the Sy/Gate MicroCell and MiniCell controllers; and other modules which mount in a register slot. A latching clamp, used to secure the modules in their slots, is located directly above the mounting slots in each of the rack assemblies. The Type RRK100 Register Rack has five register slots.