- KSK clamps - 8a, Black - They are made of special spring tempered stainless steel that can withstand hundreds of cycles without deform. - This material has ideal spring action for Rubber Dam Clamps, as well as maximum corrosion resistance.Every production lot is examined by metal fatigue test which assures good spring action and long life time. - Black clamps provide very less light reflection protecting the eyes especially when working with microscopes. **For further product information, please contact Chat Support**