A new generation of PS/2 keyboard adapter boards allowing simultaneous dual PS/2 keyboards when combined with a
Y-Splitter Cable on select versions of the TK-II hardware.

Dual PS/2 keyboard capability is only available in the TK-II-GS or 1088XEL, and in some of the older board designs (see archives).
 
The TK-II is designed to take over the duties of the stock keyboard on any Atari 8-Bit computer system, as well as the XE Gaming Console and the 7800XM. Giving you the flexibility and choice inherent in a multitude of PS/2 keyboards available on the open market.

The TK-II can either take over completely, as is the case for the TK-II-GS model, or serve as an adjunct to the original stock keyboard, allowing both to work in concert. 

No matter which one you pick, all of the TK-II PS/2 keyboard adapters possess a very similar feature set and capabilities, with the only real difference being the way in which the board is meant to be installed