Smart Wrench (Clamp ratchet wrench) is an open-ended multi-size ratchet wrench. The ratcheting mechanism allows the nut to be clamped-on or loosened with a reciprocating motion; flip the wrench to change direction of the drive. The wrench takes the advantage of the clamp action to allow multiple sizes in both SAE and metric standards. Each wrench allows up to 3 non-metric sizes and 3 metric sizes.