Error correcting section holds PTS and DTS of the frame immediately preceding the current frame and the most recent CPTS as determined to be correct in the past. The hat includes a primary sweatband and an adjustable secondary sweatband which is removably secured at both of its opposing first and second ends to the primary sweatband. A left thigh brace is carried in the cockpit for receiving the left thigh of the kayaker having contoured outer and inner thigh braces for bracing respective outer and inner thigh portions of the kayaker’s left thigh when in the seated position. The embodiments pertain to IPL having absolute stereo-structure. The annular opening releases the second gas at a pressure and velocity sufficient to intermix with first gas released from the post while simultaneously forcing any unreacted gas and gaseous mixtures away from the tip of the post and frontal surface of the faceplate, thereby avoiding depositing contaminants thereon.