Springs
 

Boy did we miss this one. Springs were left off of the additional materials list.

Yes you can use springs as long as they are off-shelf ( not custom made ). Please remember that springs store energy and may be dangerous when the stored energy is released unexpectedly.

I hope this has not caused any great problem in your design. Since they have been legal all previous years the vetreans most likley did not even think about it.

More spring clarification
 

Does the definition of "spring" include constant force springs and bungees, as long as they are not "custom made"?