The piston is a cross between the motion system and the energyrail plate from 2 years back. It is a plate and piston with a marker binding built into it that sits on two rails that it obviously slides on. The binding is attached to these rails by what looks like 4 screws from the side. The two in the front look like clamp type of screws that are free moving and able to slide ont he rail and the rear screws look as if they are fixed but serve as an axis for the ski to flex around. therefore it is a floating toe and a fixed heel, but the whole system flexes.
As to your question about using another marker binding: You would have to get a ski that did not have the rails on it, i believe they are built into the ski (this not be true because i was told that the plate could mount to any skis - if the rails are not premounted that it would be possible to use the binding for any ski or not use the binding at all on volkl skis - although it is marketed ass a system...). Volkl does sell versions of this ski without the piston plate. There is currently a brand new pair of 170's on ebay for $250 without the piston binding.
ps. NCskier: The 21m radius may have only been going into effect for the shorter langths as i believe the longer lengths should be well over 21 m and someone who is a strong skier would want a larger radius for racing. I'll see if i can scout out the dimensions of all the lengths for you.
<FONT COLOR="#800080" SIZE="1">[ March 21, 2002 05:39 AM: Message edited 1 time, by Heluvaskier ]</font>