This paper presents a new patent pending Wave Energy Converter (WEC) named REEFS (Renewable Electric Energy From Sea). REEFS can harness both, potential energy as well as kinetic energy, of sea waves. Its structure consists of a nearshore fixed submerged caisson placed on the seabed at low depth. REEFS can contribute to shore protection because it originates storm waves breaking like natural reefs do. Due to its stay vanes and variable porosity enveloping surface the REEFS WEC creates an inner sea water flow that drives a low head turbine located inside the device. In this paper a detailed description of the REEFS concept comprising its most relevant characteristics and its theoretical functioning principles is presented. The 1.5:100 small scale laboratory functional proof of concept is described and the corresponding results that confirmed the theoretical expectations are reported. Based on the experimental results, conclusions about the potential of the REEFS wave energy harnessing concept are presented.