CS Unitec Extension for Box Wrenches, Aluminum Bronze CS Unitec Non-Sparking / Non-Magnetic Extension for Box Wrenches are a part of CS Unitecs Non-Sparking/Non-Magnetic and corrosion resistant Safety Tool Line. CS Unitec Non-Magnetic Extension for Box Wrenches are specifically designed to eliminate the risk of sparks at high-risk sites where explosive atmospheres may be present. CS Unitec Non-Sparking Extension for Box Wrenches are available in Aluminum Bronze. CS Unitec Non-Magnetic Extension for Box Wrenches are designed to loossen and tighten nuts and bolts in tight or narrow places. CS Unitecs Non-Sparking Extension for Box Wrenches are drop forged for the highest quality in hand tools.