Here's what other sites are saying:
Changing crampon sizes is a snap with the Grivel Valter Long Bar. Simply turn over the bar, and the retaining tooth automatically reduces size without tools or meticulous adjustment. Just be sure to keep track of right and left and you're good to go.
Grivel Crampon Center Bar The SPECS Materials: ChroMoly Steel Weight: Standard: 94 (pair) Weight: Long: 110 (pair)
Extender Bars from Grivel allow crampons to be used with boots of size 11 and greater on G10, G12, G14 and Airtech Crampons.
- Mountain Gear