Industrial Micro Systems - 32 K Static RAM
This was a very reliable Static RAM board.

The board could be addressed to any 4K hex boundary. The MWRT signal could be generated on the board for systems that did not have a front panel (like the IMS systems).  The phantom line was recognized. The board had a simple "memory management" circuit that allowed multiple 16K boards to reside at the same address and be switched in or out. The default port to do this was 7FH but the port can be selected with jumpers. The POC option (S-100 pin 99) was implemented with jumper J3.  The board utilized 5257 RAM chips.   
 
The manual for this board can be obtained here.

Other IMS S-100 Boards
16K RAM   32K RAM    64K DRAM    80186 CPU    FDC 400    FDC 930    HDC    IO Board    Z80 CPU  
8K RAM   4 Line Serial     CPZ 4800   LANS100    CPS-Q6A   Other Boards