The top of the line Wilton® Spark-Duty TM series with copper spindle is superior when resisting welding spatter. Every Spark-Duty F-Clamp comes standard with an ergonomic, anti-fatigue Wilton-Grip® and V-Groove pad accessory. Boasting a lifetime warranty, the 2400S series F-Clamps clamp down with 2400 pounds of force.