Regular and Lightweight Options:
There are two reasons to upgrade to the Rolling In System U Springs:
Expensive, but a very worthwhile upgrade!
ATK replacement U-Springs for Hagan Ultra World Cup and ATK SL World Cup and other bindings come in sets of two.
The "lightweight" version are called "lightweight" not because they are lighter than the regular titanium U Springs found on the HAGAN Ultra World Cup bindings, but because the retention value is lighter. The standard titanium U Springs release value is approximately 8 or 9, while the "lightweight" version is approximately 5 or 6. the Side notches on the lightweight version enable the springs to flex and release at a lower force level. (No claim of DIN value is made.)
So the "lightweight" name applies more to the skiers who may want to use these U springs -- lightweight skiers!