IIRC Those things were designed to put 4 x 30pin modules (8-bit) to one 72-pin slot (32-bit). those modules had to be identical, otherwise it would not work reliably.

<div class='quotetop'>QUOTE(ZipoB @ Jun 18 2006, 12:55 PM) [snapback]237591[/snapback]</div>I used to use those on old 386/486 machines. They were basically a board extension. It plugged into the simm slot and stuck out perpendicularly from the motherboard about 3 inches. (so you needed to have room inside to make it work). Anyway it had four additional simm slots that you could plug additional simms into. Got a little cramped in there.

As stated above used to allow you to install 30 pin simms into a machine with 72 pin slots.

Here's a pic .. third image down on the right.

Link

I found one at the dump earlier today but it's dead because I went to a firneds and we tried it on his 486 which we knew would have worked with it.