"YOU ARE CORRECT, ARISTOCRAT. FIRSTLY, MAKE SURE THERE ARE CREDITS REMANING ON YOUR CYBERNETICS CREDIT WEDGE. THE INSTALLATION OF A CYBERNETIC IMPLANT COSTS ONE CREDIT." - Cybernetics Terminal when asked about "HOW DO I INSTALL A CYBERNETIC IMPLANT?"
A Cybernetics Credit Wedge only weigths 1 lbs and holds one credit.
A credit from a Cybernetics Credit Wedge is used to increase your License Points, which allows you to install more (and more powerful) Cybernetics at a Becoming Nook. Note that you must also be True Kin to use it.
Cybernetics Credit Wedges are frequently found near Becoming Nooks; you can also find or purchase them randomly in many other places.
One way to acquire cybernetic credit wedges is to perform the water ritual with an elite Putus Templar; you may ask for one in exchange for reputation.