Marker Bindings On Skis

Question about some older Marker bindings?
I just got my first pair of skis from a ski swap and they came with Marker 7.1 bindings. They also have written on the bindings “Selective Control”, “Biometric” and “Logic”. Anyways, at the toe of the binding is a lever that can be moved to a setting of 1, 2 or 3, and no one I talked to can figure out what it does. Anyone know what this setting is for?
Okay. Thanks for the info on the flex pattern. I did a little more research and found the 3 settings to be for “free flex under foot”, “resistance flex underfoot”, and “no flex underfoot”. Could I get a little more explanation on what these mean? As a beginner/intermediate skiing mostly on groomed runs, what setting should I use?That changes the flex pattern of the ski if I remember them right. It changed the tension on the mounting rail so the ski was softer or stiffer depending on what you preferred. I have a set on my rocks skis but they are in Seattle and I’m not.
This was about the same time period that ESS had their VAR binding on the market. The VAR would easily slide from one position to another from center to forward to back with the flip of a lever. This was in the mid 90′s. Lots of fun if someone grabbed your skis when you weren’t looking and moved one forward and one back.