Petzl Barrettes L
Here's what other sites are saying:
Use the Petzl Barrettes Long Linking Crampon bars to allow your Petzl crampons (sold separately) to accommodate European boot sizes 41 - 50 (US men's 8 - 15). Bars are designed for boots without high asymmetric curvature. Adjustable for half sizes. Petzl Barrettes Long Linking Crampon bars are sold in pairs.