Genuine Sidi spare parts Replacement Sidi Reinforcement Plate for all Sidi MTB shoes. These units are the female inserts to which the cleat bolts connect to through the outer sole of the shoe. If you fail to grease these threads you may have to drill your cleats out - in the event of this the inner last may be cut to access this plate and replaced with these saving your shoes. (its easier to just grease your cleat threads)