These are lightly worn size 8 black Reef Flip Flops from the mid 2000's.  They are the CO-3 Pro Model with the sponsor of professional surfer Fred Patacchia Jr. who grew up on the North Shore of Oahu, Hawaii.  He retired from the World Surf League after a perfect 10 at the Hurley Pro at Lower Trestles on September 9, 2015.