This is cool. It allows you to run a wideband O2 sensor on a narrowband input. As you may know, a narrow band O2 is only accurate at stoich. Converting the WB signal (0-5v) to NB (0-1v) makes it more accurate in closed loop. (in theory) So far I can only find them on ebay UK. The US distributor is defunk, web link dead.

It will allow O2 tuning to be more accurate if using a narrow band only ECU.

http://www.aeb.it/products/sundry-items/351

Thay have a bunch of cool stuff on thier site.