The QuikChange II system is the second generation of Agilent’s QuikChange method. It provides improved fidelity over the original kit while maintaining greater than 80% mutation efficiency for single site mutagenesis. The kit includes PfuUltra High-Fidelity DNA Polymerase to minimize unwanted errors. The kit also includes all the reagents necessary to support mutagenesis (at single sites) for large constructs, and for use with electroporation competent cells.