Wilson have released limited edition versions of their new (K) Factor tennis rackets in order to raise money for charity. The limited edition (K) Factor tennis rackets are inlaid with gold leaf designs and are available in both a black and white model. The rackets were used by Serena and Venus Williams at Wimbledon earlier this month. Only 650 of each model will be available with ten percent of the proceeds going to The Breast Cancer Research Foundation (BCRF), a charity founded in 1993 by Evelyn H. Lauder to support research on breast cancer, an additional ten rackets of each model signed by Serena and Venus Williams will be auctioned of to support the BCRF.