Why would you need two? in case one fails or something? Here is an example http://www.amazon.com/gp/product/B00CU4L6MK/ref=s9_simh_gw_p147_d0_i1?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=0QQ15AT87VJ2XAZ61MMF&pf_rd_t=101&pf_rd_p=1688200382&pf_rd_i=507846